Theory and Simulation Group

Group Leader: Pablo Ordejón

Publications

2017

  • Anisotropic features in the electronic structure of the two-dimensional transition metal trichalcogenide TiS3: Electron doping and plasmons

    Silva-Guillén J.A., Canadell E., Ordejón P., Guinea F., Roldán R. 2D Materials; 4 (2, 025085) 2017. 10.1088/2053-1583/aa6b92.

    Analysis of the band structure of TiS3 single-layers suggests the possibility of changing their physical behaviour by injecting electron carriers. The anisotropy of the valence and conduction bands is explained in terms of their complex orbital composition. The nature of the Fermi surface and Lindhard response function for different doping concentrations is studied by means of firstprinciples DFT calculations. It is suggested that for electron doping levels x (number of electrons per unit cell) ~0.18-0.30e- the system could exhibit incommensurate charge or spin modulations which, however, would keep the metallic state whereas systems doped with smaller x would be 2D metals without any electronic instability. The effect of spin-orbit coupling in the band dispersion is analysed. The DFT effective masses are used to study the plasmon spectrum from an effective low energy model. We find that this material supports highly anisotropic plasmons, with opposite anisotropy for the electron and hole bands.


  • Voltage-Induced Coercivity Reduction in Nanoporous Alloy Films: A Boost toward Energy-Efficient Magnetic Actuation

    Quintana A., Zhang J., Isarain-Chávez E., Menéndez E., Cuadrado R., Robles R., Baró M.D., Guerrero M., Pané S., Nelson B.J., Müller C.M., Ordejón P., Nogués J., Pellicer E., Sort J. Advanced Functional Materials; 2017. 10.1002/adfm.201701904.

    Magnetic data storage and magnetically actuated devices are conventionally controlled by magnetic fields generated using electric currents. This involves significant power dissipation by Joule heating effect. To optimize energy efficiency, manipulation of magnetic information with lower magnetic fields (i.e., lower electric currents) is desirable. This can be accomplished by reducing the coercivity of the actuated material. Here, a drastic reduction of coercivity is observed at room temperature in thick (≈600 nm), nanoporous, electrodeposited Cu-Ni films by simply subjecting them to the action of an electric field. The effect is due to voltage-induced changes in the magnetic anisotropy. The large surface-area-to-volume ratio and the ultranarrow pore walls of the system allow the whole film, and not only the topmost surface, to effectively contribute to the observed magnetoelectric effect. This waives the stringent "ultrathin-film requirement" from previous studies, where small voltage-driven coercivity variations were reported. This observation expands the already wide range of applications of nanoporous materials (hitherto in areas like energy storage or catalysis) and it opens new paradigms in the fields of spintronics, computation, and magnetic actuation in general. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


2016

  • AFM Imaging of Mercaptobenzoic Acid on Au(110): Submolecular Contrast with Metal Tips

    Hauptmann N., Robles R., Abufager P., Lorente N., Berndt R. Journal of Physical Chemistry Letters; 7 (11): 1984 - 1990. 2016. 10.1021/acs.jpclett.6b00684. IF: 8.539

    A self-assembled monolayer of mercaptobenzoic acid (MBA) on Au(110) is investigated with scanning tunneling and atomic force microscopy (STM and AFM) and density functional calculations. High-resolution AFM images obtained with metallic tips show clear contrasts between oxygen atoms and phenyl moieties. The contrast above the oxygen atoms is due to attractive covalent interactions, which is different than previously reported high-resolution images, where Pauli repulsion dominated the image contrast. We show that the bonding of MBA to the substrate occurs mainly through dispersion interactions, whereas the thiol-Au bond contributes only a quarter of the adsorption energy. No indication of Au adatoms mediating the thiol-Au interaction was found in contrast to other thiol-bonded systems. However, MBA lifts the Au(110)-(2 × 1) reconstruction. © 2016 American Chemical Society.


  • Effect of asymmetric concentration profile on thermal conductivity in Ge/SiGe superlattices

    Hahn K.R., Cecchi S., Colombo L. Applied Physics Letters; 108 (20, 203102) 2016. 10.1063/1.4949491. IF: 3.142

    The effect of the chemical composition in Si/Ge-based superlattices on their thermal conductivity has been investigated using molecular dynamics simulations. Simulation cells of Ge/SiGe superlattices have been generated with different concentration profiles such that the Si concentration follows a step-like, a tooth-saw, a Gaussian, and a gamma-type function in direction of the heat flux. The step-like and tooth-saw profiles mimic ideally sharp interfaces, whereas Gaussian and gamma-type profiles are smooth functions imitating atomic diffusion at the interface as obtained experimentally. Symmetry effects have been investigated comparing the symmetric profiles of the step-like and the Gaussian function to the asymmetric profiles of the tooth-saw and the gamma-type function. At longer sample length and similar degree of interdiffusion, the thermal conductivity is found to be lower in asymmetric profiles. Furthermore, it is found that with smooth concentration profiles where atomic diffusion at the interface takes place the thermal conductivity is higher compared to systems with atomically sharp concentration profiles. © 2016 Author(s).


  • Electronic structure of 2H-NbSe2 single-layers in the CDW state

    Silva-Guillén J.Á., Ordejón P., Guinea F., Canadell E. 2D Materials; 3 (3, 035028) 2016. 10.1088/2053-1583/3/3/035028. IF: 9.611

    Adensity functional theory study of NbSe2"Qsingle-layers in the normal non-modulated and the 3"Q¡Ñ"Q3 CDWstates is reported.Weshow that, in the single layer, the CDW barely affects the Fermi surface of the system, thus ruling out a nesting mechanism as the driving force for the modulation. The CDW stabilizes levels lying around 1.35 eV below the Fermi level within the Se-based valence band but having a substantial Nb-VNb bonding character. The absence of interlayer interactions leads to the suppression of the pancake-like portion of the bulk Fermi surface in the single-layer.Weperform scanning tunneling microscopy simulations and find that the images noticeably change with the sign and magnitude of the voltage bias. The atomic corrugation of the Se sublayer induced by the modulation plays a primary role in leading to these images, but the electronic reorganization also has an important contribution. The analysis of the variation of these images with the bias voltage does not support a Fermi surface nesting mechanism for the CDW. It is also shown that underlying graphene layers (present in some of the recent experimental work) do not modify the conduction band, but do affect the shape of the valence band of NbSe2"Qsingle-layers. The relevance of these results in understanding recent physical measurements for NbSe2"Qsingle-layers is discussed. © 2016 IOP Publishing Ltd.


  • Following the steps of a reaction by direct imaging of many individual molecules

    Van Vörden D., Wortmann B., Schmidt N., Lange M., Robles R., Brendel L., Bobisch C.A., Möller R. Chemical Communications; 52 (49): 7711 - 7714. 2016. 10.1039/c6cc02959k. IF: 6.567

    The dehydrogenation and dechlorination of FeOEP-Cl on Cu(111) has been studied in detail by scanning tunneling microscopy. Although, it is not possible to follow the reaction of an individual molecule, the complete pathway of the reaction with 22 inequivalent intermediate states and the rates of the involved processes are revealed. This is achieved by combining the analysis of a large data set showing thousands of molecules in the different stages of the reaction with numerical simulations. © 2016 The Royal Society of Chemistry.


  • Heat transport through a solid-solid junction: The interface as an autonomous thermodynamic system

    Rurali R., Colombo L., Cartoixà X., >Øivind W., Trinh T.T., Bedeaux D., Kjelstrup S. Physical Chemistry Chemical Physics; 18 (20): 13741 - 13745. 2016. 10.1039/c6cp01872f. IF: 4.449

    We perform computational experiments using nonequilibrium molecular dynamics simulations, showing that the interface between two solid materials can be described as an autonomous thermodynamic system. We verify the local equilibrium and give support to the Gibbs description of the interface also away from the global equilibrium. In doing so, we reconcile the common formulation of the thermal boundary resistance as the ratio between the temperature discontinuity at the interface and the heat flux with a more rigorous derivation from nonequilibrium thermodynamics. We also show that thermal boundary resistance of a junction between two pure solid materials can be regarded as an interface property, depending solely on the interface temperature, as implicitly assumed in some widely used continuum models, such as the acoustic mismatch model. Thermal rectification can be understood on the basis of different interface temperatures for the two flow directions. © The Owner Societies 2016.


  • How disorder affects topological surface states in the limit of ultrathin Bi2Se3 films

    Song K., Soriano D., Robles R., Ordejon P., Roche S. 2D Materials; 3 (4, 045007) 2016. 10.1088/2053-1583/3/4/045007. IF: 9.611

    We present a first-principles study of electronic properties of ultrathin films of topological insulators (TIs) and scrutinize the role of disorder on the robustness of topological surface states, which can be analysed through their spin textures. The presence of twin grain boundaries is found to increase the band gap of the film, while preserving the spin texture of states in first conduction and valence bands. Differently, partial hydrogenation of one surface not only results in some self-doping effect, but also provokes some alteration of the spin texture symmetry of the electronic states. The formation of a new Dirac cone at M-point of the Brillouin zone of the hydrogenated surface, together with a modified spin texture characteristics are consistent with a dominant Dresselhaus spin-orbit interaction type, more usually observed in 3D materials. Our findings indicate that defects can either be detrimental or beneficial for exploring spin transport of surface states in the limit of ultrathin films of TIs, which maximizes surface over bulk phenomena. © 2016 IOP Publishing Ltd.


  • In-plane/out-of-plane disorder influence on the magnetic anisotropy of Fe1- yMnyPt-L10 bulk alloy

    Cuadrado R., Liu K., Klemmer T.J., Chantrell R.W. Applied Physics Letters; 108 (12, 123102) 2016. 10.1063/1.4944534. IF: 3.142

    The random substitution of a non-magnetic species instead of Fe atoms in FePt-L10 bulk alloy will permit to tune the magnetic anisotropy energy of this material. We have performed by means of first principles calculations a study of Fe1- yMnyPt-L10 (y = 0.0, 0.08, 0.12, 0.17, 0.22, and 0.25) bulk alloy for a fixed Pt concentration when the Mn species have ferro-/antiferromagnetic (FM,AFM) alignment at the same(different) atomic plane(s). This substitution will promote several in-plane lattice values for a fixed amount of Mn. Charge hybridization will change compared to the FePt-L10 bulk due to this lattice variation leading to a site resolved magnetic moment modification. We demonstrate that this translates into a total magnetic anisotropy reduction for the AFM phase and an enhancement for the FM alignment. Several geometric configurations were taken into account for a fixed Mn concentration because of different possible Mn positions in the simulation cell. © 2016 AIP Publishing LLC.


  • Nanotexturing to Enhance Photoluminescent Response of Atomically Thin Indium Selenide with Highly Tunable Band Gap

    Brotons-Gisbert M., Andres-Penares D., Suh J., Hidalgo F., Abargues R., Rodríguez-Cantó P.J., Segura A., Cros A., Tobias G., Canadell E., Ordejón P., Wu J., Martínez-Pastor J.P., Sánchez-Royo J.F. Nano Letters; 16 (5): 3221 - 3229. 2016. 10.1021/acs.nanolett.6b00689. IF: 13.779

    Manipulating properties of matter at the nanoscale is the essence of nanotechnology, which has enabled the realization of quantum dots, nanotubes, metamaterials, and two-dimensional materials with tailored electronic and optical properties. Two-dimensional semiconductors have revealed promising perspectives in nanotechnology. However, the tunability of their physical properties is challenging for semiconductors studied until now. Here we show the ability of morphological manipulation strategies, such as nanotexturing or, at the limit, important surface roughness, to enhance light absorption and the luminescent response of atomically thin indium selenide nanosheets. Besides, quantum-size confinement effects make this two-dimensional semiconductor to exhibit one of the largest band gap tunability ranges observed in a two-dimensional semiconductor: from infrared, in bulk material, to visible wavelengths, at the single layer. These results are relevant for the design of new optoelectronic devices, including heterostructures of two-dimensional materials with optimized band gap functionalities and in-plane heterojunctions with minimal junction defect density. © 2016 American Chemical Society.


  • Noncontact atomic force microscopy and density functional theory studies of the (2×2) reconstructions of the polar AlN(0001) surface

    Chaumeton F., Robles R., Pruneda M., Lorente N., Eydoux B., Bouju X., Gauthier S., Martrou D. Physical Review B - Condensed Matter and Materials Physics; 94 (16, 165305) 2016. 10.1103/PhysRevB.94.165305. IF: 3.718

    Combined experimental and theoretical studies permit us to determine new protocols for growing by molecular beam epitaxy the technologically interesting N-rich aluminum nitride (AlN) surfaces. This is achieved by dosing the precursor gases at unusually low rates. With the help of calculated structures by using density functional theory and Boltzmann distribution of the reconstructed cells, we proposed to assign the measured surface obtained with a growth rate of 10 nm/h to a (2×2) reconstructed surface involving one additional N atom per unit cell. These N-rich AlN surfaces could open new routes to dope AlN layers with important implications in high-power and temperature technological applications. © 2016 American Physical Society.


  • On-Surface Engineering of a Magnetic Organometallic Nanowire

    Ormaza M., Robles R., Bachellier N., Abufager P., Lorente N., Limot L. Nano Letters; 16 (1): 588 - 593. 2016. 10.1021/acs.nanolett.5b04280. IF: 13.779

    The manipulation of the molecular spin state by atom doping is an attractive strategy to confer desirable magnetic properties to molecules. Here, we present the formation of novel magnetic metallocenes by following this approach. In particular, two different on-surface procedures to build isolated and layer-integrated Co-ferrocene (CoFc) molecules on a metallic substrate via atomic manipulation and atom deposition are shown. The structure as well as the electronic properties of the so-formed molecule are investigated combining scanning tunneling microscopy and spectroscopy with density functional theory calculations. It is found that unlike single ferrocene a CoFc molecule possesses a magnetic moment as revealed by the Kondo effect. These results correspond to the first controlled procedure toward the development of tailored metallocene-based nanowires with a desired chemical composition, which are predicted to be promising materials for molecular spintronics. © 2015 American Chemical Society.


  • Optical Absorption Spectra and Excitons of Dye-Substrate Interfaces: Catechol on TiO2(110)

    Mowbray D.J., Migani A. Journal of Chemical Theory and Computation; 12 (6): 2843 - 2852. 2016. 10.1021/acs.jctc.6b00217. IF: 5.301

    Optimizing the photovoltaic efficiency of dye-sensitized solar cells (DSSC) based on staggered gap heterojunctions requires a detailed understanding of sub-band gap transitions in the visible from the dye directly to the substrate's conduction band (CB) (type-II DSSCs). Here, we calculate the optical absorption spectra and spatial distribution of bright excitons in the visible region for a prototypical DSSC, catechol on rutile TiO2(110), as a function of coverage and deprotonation of the OH anchoring groups. This is accomplished by solving the Bethe-Salpeter equation (BSE) based on hybrid range-separated exchange and correlation functional (HSE06) density functional theory (DFT) calculations. Such a treatment is necessary to accurately describe the interfacial level alignment and the weakly bound charge transfer transitions that are the dominant absorption mechanism in type-II DSSCs. Our HSE06 BSE spectra agree semiquantitatively with spectra measured for catechol on anatase TiO2 nanoparticles. Our results suggest deprotonation of catechol's OH anchoring groups, while being nearly isoenergetic at high coverages, shifts the onset of the absorption spectra to lower energies, with a concomitant increase in photovoltaic efficiency. Further, the most relevant bright excitons in the visible region are rather intense charge transfer transitions with the electron and hole spatially separated in both the [110] and [001] directions. Such detailed information on the absorption spectra and excitons is only accessible via periodic models of the combined dye-substrate interface. © 2016 American Chemical Society.


  • Reversible 2D Phase Transition Driven by an Electric Field: Visualization and Control on the Atomic Scale

    Wortmann B., Vörden D.V., Graf P., Robles R., Abufager P., Lorente N., Bobisch C.A., Möller R. Nano Letters; 16 (1): 528 - 533. 2016. 10.1021/acs.nanolett.5b04174. IF: 13.779

    We report on a reversible structural phase transition of a two-dimensional system that can be locally induced by an external electric field. Two different structural configurations may coexist within a CO monolayer on Cu(111). The balance between the two phases can be shifted by an external electric field, causing the domain boundaries to move, increasing the area of the favored phase controllable both in location and size. If the field is further enhanced new domains nucleate. The arrangement of the CO molecules on the Cu surface is observed in real time and real space with atomic resolution while the electric field driving the phase transition is easily varied over a broad range. Together with the well-known molecular manipulation of CO adlayers, our findings open exciting prospects for combining spontaneous long-range order with man-made CO structures such as "molecule cascades" or "molecular graphene". Our new manipulation mode permits us to bridge the gap between fundamental concepts and the fabrication of arbitrary atomic patterns in large scale, by providing unprecedented insight into the physics of structural phase transitions on the atomic scale. © 2015 American Chemical Society.


  • Spin-polarised edge states in atomic Mn chains supported on Cu2N/Cu (100)

    Choi D.-J., Robles R., Gauyacq J.-P., Rubio-Verdú C., Lorente N., Ignacio Pascual J. Journal of Physics Condensed Matter; 28 (23, 23LT01) 2016. 10.1088/0953-8984/28/23/23LT01. IF: 2.209

    Scanning tunnelling microscopy and density functional theory studies of manganese chains adsorbed on Cu2N/Cu (100) reveal an unsuspected electronic edge state at ∼ 1 eV above the Fermi energy. This Tamm-like state is strongly localised to the terminal Mn atoms of the chain and fully spin polarised. However, no equivalence is found for occupied states, and the electronic structure at ∼ -1 eV is mainly spin unpolarised due to the extended p-states of the N atoms that mediate the coupling between the Mn atoms in the chain. The spin polarisation of the edge state is affected by the antiferromagnetic ordering of the chains leading to non-trivial consequences. © 2016 IOP Publishing Ltd.


  • Structural and magnetic properties of FeMnx chains (x=1-6) supported on Cu2 N/Cu (100)

    Choi D.-J., Robles R., Gauyacq J.-P., Ternes M., Loth S., Lorente N. Physical Review B - Condensed Matter and Materials Physics; 94 (8, 085406) 2016. 10.1103/PhysRevB.94.085406. IF: 3.718

    Heterogeneous atomic magnetic chains are built by atom manipulation on a Cu2N/Cu (100) substrate. Their magnetic properties are studied and rationalized by a combined scanning tunneling microscopy (STM) and density functional theory (DFT) work completed by model Hamiltonian studies. The chains are built using Fe and Mn atoms ontop of the Cu atoms along the N rows of the Cu2N surface. Here, we present results for FeMnx chains (x=1-6) emphasizing the evolution of the geometrical, electronic, and magnetic properties with chain size. By fitting our results to a Heisenberg Hamiltonian we have studied the exchange-coupling matrix elements J for different chains. For the shorter chains, x≤2, we have included spin-orbit effects in the DFT calculations, extracting the magnetic anisotropy energy. Our results are also fitted to a simple anisotropic spin Hamiltonian and we have extracted values for the longitudinal-anisotropy D and transversal-anisotropy E constants. These parameters together with the values for J allow us to compute the magnetic excitation energies of the system and to compare them with the experimental data. © 2016 American Physical Society.


  • Surface cis Effect: Influence of an Axial Ligand on Molecular Self-Assembly

    Knaak T., Gopakumar T.G., Schwager B., Tuczek F., Robles R., Lorente N., Berndt R. Journal of the American Chemical Society; 138 (24): 7544 - 7550. 2016. 10.1021/jacs.6b03710. IF: 13.038

    Adding ligands to molecules can have drastic and unforeseen consequences in the final products of a reaction. Recently a surface trans effect due to the weakening of a molecule-surface bond was reported. Here, we show a surface cis effect where an axial ligand at adsorbed transition-metal complexes enables lateral bonding among the molecules. In the absence of this ligand, the intermolecular interaction is repulsive and supramolecular patterns are not observed. Fe-tetramethyl-tetraazaannulene on Au(111) was investigated using low-temperature scanning tunneling microscopy and spectroscopy along with density functional theory calculations. At low coverages, the molecules remain isolated. Exposure to CO leads to axial CO bonding and induces reordering into extended clusters of chiral molecular trimers. The changed self-assembly pattern is due to a CO-induced modification of the molecular structure and the corresponding charge transfer between the molecule and the substrate, which in turn changes the lateral intermolecular forces. © 2016 American Chemical Society.


  • Theoretical studies of Rashba and Dresselhaus effects in hybrid organic-inorganic perovskites for optoelectronic applications

    Pedesseau L., Kepenekian M., Robles R., Sapori D., Katan C., Even J. Proceedings of SPIE - The International Society for Optical Engineering; 9742 ( 97421B) 2016. 10.1117/12.2213618. IF: 0.000

    In this paper, we propose a description of the Rashba-Dresselhaus effect in Hybrid Organic Perovskite (HOP). We show how the loss of the inversion symmetry leads to the loss of the spin degeneracy. An example of structure where both Rashba and Dresselhaus operate is illustrated with the formamidinium tin iodide CH(NH2)2SnI3. The control of this effect is as well addressed by two examples. A first example concerns the control with the temperature and is demonstrated for the 2D HOP Bz2PbCl4 (Bz = benzylammonium). Then the control with an external field is established for the 3D HOP CH3NH3PbBr3. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.


  • Thermal conductivity of MoS2 polycrystalline nanomembranes

    Sledzinska M., Graczykowski B., Placidi M., Reig D.S., El Sachat A., Reparaz J.S., Alzina F., Mortazavi B., Quey R., Colombo L., Roche S., Torres C.M.S. 2D Materials; 3 (3, 035016) 2016. 10.1088/2053-1583/3/3/035016. IF: 9.611

    Heat conduction in 2D materials can be effectively engineered by means of controlling nanoscale grain structure. Afavorable thermal performance makes these structures excellent candidates for integrated heat management units. Here we show combined experimental and theoretical studies for MoS2 nanosheets in a nanoscale grain-size limit.Wereport thermal conductivity measurements on 5 nm thick polycrystalline MoS2 by means of 2-laser Raman thermometry. The free-standing, drum-like MoS2 nanomembranes were fabricated using a novel polymer- and residue-free, wet transfer, in which we took advantage of the difference in the surface energies between MoS2 and the growth substrate to transfer the CVD-grown nanosheets. The measurements revealed a strong reduction in the in-plane thermal conductivity down to about 0.73 ± 0.25 W m-1 K-1. The results are discussed theoretically using finite elements method simulations for a polycrystalline film, and a scaling trend of the thermally conductivity with grain size is proposed. © 2016 IOP Publishing Ltd.


  • Thermal rectification in silicon by a graded distribution of defects

    Dettori R., Melis C., Rurali R., Colombo L. Journal of Applied Physics; 119 (21, 215102) 2016. 10.1063/1.4953142. IF: 2.101

    We discuss about computer experiments based on nonequilibrium molecular dynamics simulations providing evidence that thermal rectification can be obtained in bulk Si by a non-uniform distribution of defects. We consider a graded population of both Ge substitutional defects and nanovoids, distributed along the direction of an applied thermal bias, and predict a rectification factor comparable to what is observed in other low-dimensional Si-based nanostructures. By considering several defect distribution profiles, thermal bias conditions, and sample sizes, the present results suggest that a possible way for tuning the thermal rectification is by defect engineering. © 2016 Author(s).


  • Thermal transport in porous Si nanowires from approach-to-equilibrium molecular dynamics calculations

    Cartoixà X., Dettori R., Melis C., Colombo L., Rurali R. Applied Physics Letters; 109 (1, 013107) 2016. 10.1063/1.4955038. IF: 3.142

    We study thermal transport in porous Si nanowires (SiNWs) by means of approach-to-equilibrium molecular dynamics simulations. We show that the presence of pores greatly reduces the thermal conductivity, κ, of the SiNWs as long mean free path phonons are suppressed. We address explicitly the dependence of κ on different features of the pore topology - such as the porosity and the pore diameter - and on the nanowire (NW) geometry - diameter and length. We use the results of the molecular dynamics calculations to tune an effective model, which is capable of capturing the dependence of κ on porosity and NW diameter. The model illustrates the failure of Matthiessen's rule to describe the coupling between boundary and pore scattering, which we account for by the inclusion of an additional empirical term. © 2016 Author(s).


2015

  • Assembly of ferrocene molecules on metal surfaces revisited

    Ormaza M., Abufager P., Bachellier N., Robles R., Verot M., Le Bahers T., Bocquet M.-L., Lorente N., Limot L. Journal of Physical Chemistry Letters; 6 (3): 395 - 400. 2015. 10.1021/jz5026118. IF: 7.458

    Metallocene (MCp2) wires have recently attracted considerable interest in relation to molecular spintronics due to predictions concerning their half-metallic nature. This exciting prospect is however hampered by the little and often-contradictory knowledge we have concerning the metallocene self-assembly and interaction with a metal. Here, we elucidate these aspects by focusing on the adsorption of ferrocene on Cu(111) and Cu(100). Combining low-temperature scanning tunneling microscopy and density functional theory calculations, we demonstrate that the two-dimensional molecular arrangement consists of vertical- and horizontal-lying molecules. The noncovalent T-shaped interactions between Cp rings of vertical and horizontal molecules are essential for the stability of the physisorbed molecular layer. These results provide a fresh insight into ferrocene adsorption on surfaces and may serve as an archetypal reference for future work with this important variety of organometallic molecules. (Figure Presented). © 2015 American Chemical Society.


  • Capacitive DNA Detection Driven by Electronic Charge Fluctuations in a Graphene Nanopore

    Feliciano G.T., Sanz-Navarro C., Coutinho-Neto M.D., Ordejón P., Scheicher R.H., Rocha A.R. Physical Review Applied; 3 (3, 034003) 2015. 10.1103/PhysRevApplied.3.034003. IF: 0.000

    The advent of parallelized automated methods for rapid whole-genome analysis has led to an exponential drop in costs, thus greatly accelerating biomedical research and discovery. Third-generation sequencing techniques, which would utilize the characteristic electrical conductance of the four different nucleotides, could facilitate longer base read lengths and an even lower price per genome. In this work, we propose and apply a quantum-classical hybrid methodology to quantitatively determine the influence of the solvent on the dynamics of DNA and the resulting electron transport properties of a prototypic sequencing device utilizing a graphene nanopore through which the nucleic-acid chain is threaded. Our results show that charge fluctuations in the nucleotides are responsible for characteristic conductance modulations in this system, which can be regarded as a field-effect transistor tuned by the dynamic aqueous environment. © 2015 American Physical Society.


  • Comparing Quasiparticle H2O Level Alignment on Anatase and Rutile TiO2

    Sun H., Mowbray D.J., Migani A., Zhao J., Petek H., Rubio A. ACS Catalysis; 5 (7): 4242 - 4254. 2015. 10.1021/acscatal.5b00529. IF: 9.312

    Knowledge of the alignment of molecular frontier levels in the ground state can be used to predict the photocatalytic activity of an interface. The position of the adsorbate's highest occupied molecular orbital (HOMO) levels relative to the substrate's valence band maximum (VBM) in the interface describes the favorability of photogenerated hole transfer from the VBM to the adsorbed molecule. This is a key quantity for assessing and comparing H2O photooxidation activities on two prototypical photocatalytic TiO2 surfaces: anatase (A)-TiO2(101) and rutile (R)-TiO2(110). Using the projected density of states (DOS) from state-of-the-art quasiparticle (QP) G0W0 calculations, we assess the relative photocatalytic activity of intact and dissociated H2O on coordinately unsaturated (Ticus) sites of idealized stoichiometric A-TiO2(101)/R-TiO2(110) and bridging O vacancies (Obr vac) of defective A-TiO2-x(101)/R-TiO2-x(110) surfaces (x = 1/4, 1/8) for various coverages. Such a many-body treatment is necessary to correctly describe the anisotropic screening of electron-electron interactions at a photocatalytic interface and, hence, obtain accurate interfacial level alignments. The more favorable ground state HOMO level alignment for A-TiO2(101) may explain why the anatase polymorph shows higher photocatalytic activities than the rutile polymorph. Our results indicate that (1) hole trapping is more favored on A-TiO2(101) than R-TiO2(110) and (2) HO@Ticus is more photocatalytically active than intact H2O@Ticus. © 2015 American Chemical Society.


  • Electromechanical response at polar zigzag boundaries in hybrid monolayers

    Martinez-Gordillo R., Pruneda M. Physical Review B - Condensed Matter and Materials Physics; 91 (4, 045411) 2015. 10.1103/PhysRevB.91.045411. IF: 3.736

    First-principles calculations are used to demonstrate electromechanical control of charge and spin at zigzag-edged interfaces between graphene and boron-nitride domains in hybrid monolayers. We show how, through a direct piezoelectric effect, the interfacial bound charges and associated electric fields can be tuned by application of an external mechanical force (stress) on the system. This results in mechanical control of the edge magnetization (piezomagnetic effect), and the possibility to transform a semiconducting heterostructure into a half-metal. The inverse effect (application of an external electric field to induce a mechanical deformation) goes together with a magnetoelectric response, which under ideal conditions we estimate to be comparable to that of prototypical Cr2O3. These effects originate from the magnetic properties of graphene's zigzag edges and the dielectric properties of the boron-nitride domain, and can also be expected in any other coplanar heterostructures with polar discontinuities. © 2015 American Physical Society.


  • FeCoCp3 Molecular Magnets as Spin Filters

    Abufager P.N., Robles R., Lorente N. Journal of Physical Chemistry C; 119 (22): 12119 - 12129. 2015. 10.1021/acs.jpcc.5b01839. IF: 4.772

    Metallorganic molecules have been proposed as excellent spin filters in molecular spintronics because of the large spin polarization of their electronic structure. However, most of the studies involving spin transport have disregarded fundamental aspects such as the magnetic anisotropy of the molecule and the excitation of spin-flip processes during electron transport. Here, we study a molecule containing a Co and an Fe atom stacked between three cyclopentadienyl rings, which presents a large magnetic anisotropy and a S = 1. These figures are superior to other molecules with the same transition metal and improves the spin-filtering capacities of the molecule. Nonequilibrium Green's functions calculations based on density functional theory predict excellent spin-filtering properties both in tunnel and contact transport regimes. However, exciting the first magnetic state drastically reduces the current's spin polarization. Furthermore, a difference of temperature between electrodes leads to strong thermoelectric effects that also suppress spin polarization. Our study shows that in principle good molecular candidates for spintronics need to be confronted with inelastic and thermoelectric effects. (Graph Presented). © 2015 American Chemical Society.


  • Polar discontinuities and 1D interfaces in monolayered materials

    Martinez-Gordillo R., Pruneda M. Progress in Surface Science; 90 (4): 444 - 463. 2015. 10.1016/j.progsurf.2015.08.001. IF: 5.696

    Interfaces are the birthplace of a multitude of fascinating discoveries in fundamental science, and have enabled modern electronic devices, from transistors, to lasers, capacitors or solar cells. These interfaces between bulk materials are always bi-dimensional (2D) 'surfaces'. However the advent of graphene and other 2D crystals opened up a world of possibilities, as in this case the interfaces become one-dimensional (1D) lines. Although the properties of 1D nanoribbons have been extensively discussed in the last few years, 1D interfaces within infinite 2D systems had remained mostly unexplored until very recently. These include grain boundaries in polycrystalline samples, or interfaces in hybrid 2D sheets composed by segregated domains of different materials (as for example graphene/BN hybrids, or chemically different transition metal dichalcogenides). As for their 2D counterparts, some of these 1D interfaces exhibit polar characteristics, and can give rise to fascinating new physical properties. Here, recent experimental discoveries and theoretical predictions on the polar discontinuities that arise at these 1D interfaces will be reviewed, and the perspectives of this new research topic, discussed. © 2015 Elsevier Ltd. All rights reserved.


  • Quasiparticle interfacial level alignment of highly hybridized frontier levels: H2O on TiO2(110)

    Migani A., Mowbray D.J., Zhao J., Petek H. Journal of Chemical Theory and Computation; 11 (1): 239 - 251. 2015. 10.1021/ct500779s. IF: 5.498

    Knowledge of the frontier levels' alignment prior to photoirradiation is necessary to achieve a complete quantitative description of H2O photocatalysis on TiO2(110). Although H2O on rutile TiO2(110) has been thoroughly studied both experimentally and theoretically, a quantitative value for the energy of the highest H2O occupied levels is still lacking. For experiment, this is due to the H2O levels being obscured by hybridization with TiO2(110) levels in the difference spectra obtained via ultraviolet photoemission spectroscopy (UPS). For theory, this is due to inherent difficulties in properly describing many-body effects at the H2O-TiO2(110) interface. Using the projected density of states (DOS) from state-of-the-art quasiparticle (QP) G0W0, we disentangle the adsorbate and surface contributions to the complex UPS spectra of H2O on TiO2(110). We perform this separation as a function of H2O coverage and dissociation on stoichiometric and reduced surfaces. Due to hybridization with the TiO2(110) surface, the H2O 3a1 and 1b1 levels are broadened into several peaks between 5 and 1 eV below the TiO2(110) valence band maximum (VBM). These peaks have both intermolecular and interfacial bonding and antibonding character. We find the highest occupied levels of H2O adsorbed intact and dissociated on stoichiometric TiO2(110) are 1.1 and 0.9 eV below the VBM. We also find a similar energy of 1.1 eV for the highest occupied levels of H2O when adsorbed dissociatively on a bridging O vacancy of the reduced surface. In both cases, these energies are significantly higher (by 0.6 to 2.6 eV) than those estimated from UPS difference spectra, which are inconclusive in this energy region. Finally, we apply self-consistent QPGW (scQPGW1) to obtain the ionization potential of the H2O-TiO2(110) interface. (Figure Presented). © 2014 American Chemical Society.


  • Quasiparticle spectra of 2H-NbSe2: Two-band superconductivity and the role of tunneling selectivity

    Noat Y., Silva-Guillén J.A., Cren T., Cherkez V., Brun C., Pons S., Debontridder F., Roditchev D., Sacks W., Cario L., Ordejón P., García A., Canadell E. Physical Review B - Condensed Matter and Materials Physics; 92 (13, 134510) 2015. 10.1103/PhysRevB.92.134510. IF: 3.736

    We have studied the superconducting state of 2H-NbSe2 by scanning tunneling spectroscopy along two different crystal orientations, the c and the a/b axes. Along the c axis a large gap is dominant in the spectra, while a smaller gap is measured along the a/b axis. We show that these spectra are accurately described by the McMillan model where the small gap is induced through the coupling to the band associated with the large gap. In order to assign the small and large gaps to specific parts of the 2H-NbSe2 Fermi surface, the electronic structure was studied using first-principles calculations. While we cannot exclude the possibility of intrinsic anisotropy of the gaps, we propose that the large gap opens in the Fermi surface cylinders located around the corner K points while the sheets located around Γ are associated with the small gap. An additional component of the Fermi surface, a selenium based pocket, plays an essential role in the tunneling process. The role of the charge density wave occurring in this material is also discussed. Finally, we are able to give a coherent description of the observed characteristics of the tunneling spectra of 2H-NbSe2 as well as the differences with 2H-NbS2 where no charge density wave state is present. Further experimental work, such as high-resolution ARPES, would be very useful to confirm our interpretation. The approach and modeling developed here could also be relevant for other compounds of the dichalcogenide family. © 2015 American Physical Society.


  • Rashba and Dresselhaus Effects in Hybrid Organic-Inorganic Perovskites: From Basics to Devices

    Kepenekian M., Robles R., Katan C., Sapori D., Pedesseau L., Even J. ACS Nano; 9 (12): 11557 - 11567. 2015. 10.1021/acsnano.5b04409. IF: 12.881

    We use symmetry analysis, density functional theory calculations, and k·p modeling to scrutinize Rashba and Dresselhaus effects in hybrid organic-inorganic halide perovskites. These perovskites are at the center of a recent revolution in the field of photovoltaics but have also demonstrated potential for optoelectronic applications such as transistors and light emitters. Due to a large spin-orbit coupling of the most frequently used metals, they are also predicted to offer a promising avenue for spin-based applications. With an in-depth inspection of the electronic structures and bulk lattice symmetries of a variety of systems, we analyze the origin of the spin splitting in two- and three-dimensional hybrid perovskites. It is shown that low-dimensional nanostructures made of CH3NH3PbX3 (X = I, Br) lead to spin splittings that can be controlled by an applied electric field. These findings further open the door for a perovskite-based spintronics. © 2015 American Chemical Society.


  • Tunneling and electronic structure of the two-gap superconductor MgB2

    Silva-Guillén J.A., Noat Y., Cren T., Sacks W., Canadell E., Ordejón P. Physical Review B - Condensed Matter and Materials Physics; 92 (6, 064514) 2015. 10.1103/PhysRevB.92.064514. IF: 3.736

    A combined experimental (superconductor-insulator-superconductor tunneling spectra) and theoretical (density functional theory) study of the two-gap superconductor MgB2 is reported. The calculations confirm that the small gap is associated with a π band mostly based on the boron pz orbitals leading to the three-dimensional band component of the Fermi surface. This channel almost completely dominates the tunneling images and spectra for c-axis-oriented samples and not the two-dimensional σ band. The origin of this effect is due to the faster decay of the electronic states associated with the boron px and py orbitals compared to those associated with the boron pz orbitals, together with the symmetry properties of the wave functions. The calculated tunneling channels and partial density of states for each band agree with the values deduced from precise fits of experimental tunneling spectra. The present approach provides a framework for the understanding of tunneling spectra and the nature of superconducting gaps of other multigap superconductors. © 2015 American Physical Society.


  • Using G0W0 Level Alignment to Identify Catechol's Structure on TiO2(110)

    Mowbray D.J., Migani A. Journal of Physical Chemistry C; 119 (34): 19634 - 19641. 2015. 10.1021/acs.jpcc.5b05392. IF: 4.772

    We perform state-of-the-art calculations for a prototypical dye sensitized solar cell: catechol on rutile TiO2(110). Catechol is often used as an anchoring group for larger more complex organic and inorganic dyes on TiO2 and forms type II heterojunctions on TiO2(110). In particular, we compare quasiparticle (QP) G0W0 with hybrid exchange correlation functional (HSE) density functional theory (DFT) calculations for the catechol-rutile TiO2(110) interface. In so doing, we provide a theoretical interpretation of ultraviolet photoemission spectroscopy (UPS) and inverse photoemission spectroscopy (IPES) experiments for this prototypical system. Specifically, we demonstrate that the position, presence, and intensity of peaks associated with catechol's HOMO, intermolecular OH-O bonds, and interfacial hydrogen bonds to the surface bridging O atoms (ObrH-C and ObrH-O) may be used to fingerprint deprotonation of catechol's OH anchoring groups. Furthermore, our results suggest deprotonation of these groups, while being nearly isoenergetic at high coverages, may significantly increase the photovoltaic efficiency of catechol-TiO2(110) interfaces. (Figure Presented). © 2015 American Chemical Society.


2014

  • Classical limit of a quantal nano-magnet in an anisotropic environment

    Gauyacq, J.P.; Lorente, N. Surface Science; 630: 325 - 330. 2014. 10.1016/j.susc.2014.07.013. IF: 1.870


  • Coverage dependence of the level alignment for methanol on TiO2(110)

    Migani, A.; Mowbray, D.J. Computational and Theoretical Chemistry; 1040-1041: 259 - 265. 2014. 10.1016/j.comptc.2014.03.007. IF: 1.368


  • Difficulties in the ab initio description of electron transport through spin filters

    Kepenekian, M.; Gauyacq, J.-P.; Lorente, N. Journal of Physics Condensed Matter; 2014. 10.1088/0953-8984/26/10/104203. IF: 2.223


  • Electron transport signature of H2 dissociation on atomic gold wires

    Zanchet, A.; Roncero, O.; Dorta-Urra, A.; Aguado, A.; Martínez, J.I.; Flores, F.; Lorente, N. Physical Review B; 90 (4) 2014. 10.1103/PhysRevB.90.041404.


  • Electronic properties of single-layer and multilayer transition metal dichalcogenides MX2 (M = Mo, W and X = S, Se)

    Roldán, R.; Silva-Guillén, J.A.; López-Sancho, M.P.; Guinea, F.; Cappelluti, E.; Ordejón, P. Annalen der Physik (Leipzig); 526 (09-oct.): 347 - 357. 2014. 10.1002/andp.201400128. IF: 1.483


  • Excitation of bond-alternating spin-1/2 Heisenberg chains by tunnelling electrons

    Gauyacq, J.P.; Lorente, N. Journal of Physics Condensed Matter; 2014. 10.1088/0953-8984/26/39/394005. IF: 2.223


  • Momentum dependence of spin-orbit interaction effects in single-Layer and multi-layer transition me tal dichalcogenides

    Roldán, R. ; López-Sancho, M.P.; Guinea, F.; Silva-Guillén, J.A.; Cappelluti, E.; Ordejón, P. 2D Materials; 2014. 10.1088/2053-1583/1/3/034003 . IF: 0.000


  • Orbital redistribution in molecular nanostructures mediated by metal-organic bonds

    Yang, Z.; Corso, M.; Robles, R.; Lotze, C.; Fitzner, R.; Mena-Osteritz, E.; Bäuerle, P.; Franke, K.J.; Pascual, J.I. ACS Nano; 8 (10): 10715 - 10722. 2014. 10.1021/nn504431e. IF: 12.033


  • Oxygen vacancies in self-assemblies of ceria nanoparticles

    Sk, M.A.; Kozlov, S.M.; Lim, K.H.; Migani, A.; Neyman, K.M. Journal of Materials Chemistry A; 2 (43): 18329 - 18338. 2014. 10.1039/c4ta02200a. IF: 0.000


  • Piezoelectric monolayers as nonlinear energy harvesters

    López-Suárez, M.; Pruneda, M.; Abadal, G.; Rurali, R. Nanotechnology; 2014. 10.1088/0957-4484/25/17/175401. IF: 3.672


  • Quasiparticle level alignment for photocatalytic interfaces

    Migani, A.; Mowbray, D.J.; Zhao, J.; Petek, H.; Rubio, A. Journal of Chemical Theory and Computation; 10 (5): 2103 - 2113. 2014. 10.1021/ct500087v. IF: 5.310


  • Spin transport in dangling-bond wires on doped H-passivated Si(100)

    Kepenekian, M.; Robles, R.; Rurali, R.; Lorente, N. Nanotechnology; 2014. 10.1088/0957-4484/25/46/465703. IF: 3.672


  • Theoretical study on the influence of the Mg2+ and Al3+ octahedral cations on the vibrational spectra of the hydroxy groups of dioctahedral 2:1 phyllosilicate models

    Hernández-Haro, N.; Ortega-Castro, J.,; Pruneda, M.,; Sainz-Díaz, C.I.,; Hernández-Laguna, A. Journal of Molecular Modeling; 20 (9): 2402. 2014. 10.1007/s00894-014-2402-6. IF: 1.867


  • Transport fingerprints at graphene superlattice Dirac points induced by a boron nitride substrate

    Martinez-Gordillo, R.; Roche, S.; Ortmann, F.; Pruneda, M. Physical Review B - Condensed Matter and Materials Physics; 2014. 10.1103/PhysRevB.89.161401. IF: 3.664


2013

  • Adsorption site determination of a molecular monolayer via inelastic tunneling

    Wegner, D.; Yamachika, R.; Zhang, X.; Wang, Y.; Crommie, M.F.; Lorente, N. Nano Letters; 13: 2346 - 2350. 2013. 10.1021/nl304081q. IF: 13.025


  • Controlled manipulation of single atoms and small molecules using the scanning tunnelling microscope

    Morgenstern, K.; Lorente, N.; Rieder, K.-H. Physica Status Solidi (B): Basic Research; 250: 1671 - 1751. 2013. 10.1002/pssb.201248392. IF: 1.489


  • Correlation-mediated processes for electron-induced switching between Néel states of Fe antiferromagnetic chains

    Gauyacq, J.-P.; Yaro, S.M.; Cartoixà, X.; Lorente, N. Physical Review Letters; 110 2013. 10.1103/PhysRevLett.110.087201. IF: 7.943


  • Electron transport through dangling-bond silicon wires on H-passivated Si(100)

    Kepenekian, M.; Novaes, F.D.; Robles, R.; Monturet, S.; Kawai, H.; Joachim, C.; Lorente, N. Journal of Physics Condensed Matter; 25 2013. 10.1088/0953-8984/25/2/025503. IF: 2.355


  • Gold and methane: A noble combination for delicate oxidation

    Mowbray, D.J.; Migani, A.; Walther, G.; Cardamone, D.M.; Rubio, A. Journal of Physical Chemistry Letters; 4: 3006 - 3012. 2013. 10.1021/jz401553p. IF: 6.585


  • Imaging the dynamics of individually adsorbed molecules

    Schaffert, J.; Cottin, M.C.; Sonntag, A.; Karacuban, H.; Bobisch, C.A.; Lorente, N.; Gauyacq, J.-P.; Möller, R. Nature Materials; 12: 223 - 227. 2013. 10.1038/nmat3527. IF: 35.749


  • Impact of vacancies on diffusive and pseudodiffusive electronic transport in graphene

    Cresti, A.; Louvet, T.; Ortmann, F.; Van Tuan, D.; Lenarczyk, P.; Huhs, G.; Roche, S. Crystals; 3 (2): 289 - 305. 2013. 10.3390/cryst3020289. IF: 0.000


  • Leakage current in atomic-size surface interconnects

    Kepenekian, M.; Robles, R.; Joachim, C.; Lorente, N. Applied Physics Letters; 103 2013. 10.1063/1.4825375. IF: 3.794


  • Level alignment of a prototypical photocatalytic system: Methanol on TiO2(110)

    Migani, A.; Mowbray, D.J.; Iacomino, A.; Zhao, J.; Petek, H.; Rubio, A. Journal of the American Chemical Society; 135: 11429 - 11432. 2013. 10.1021/ja4036994. IF: 10.677


  • Magnetic reversal of a quantum nanoferromagnet

    Gauyacq, J.P.; Lorente, N. Physical Review B - Condensed Matter and Materials Physics; 87 2013. 10.1103/PhysRevB.87.195402. IF: 3.767


  • Manganese 3×3 and √3×√3-R30 â̂̃ structures and structural phase transition on w-GaN(0001̄) studied by scanning tunneling microscopy and first-principles theory

    Chinchore, A.V.; Wang, K.; Shi, M.; Mandru, A.; Liu, Y.; Haider, M.; Smith, A.R.; Ferrari, V.; Barral, M.A.; Ordejón, P. Physical Review B - Condensed Matter and Materials Physics; 87 2013. 10.1103/PhysRevB.87.165426. IF: 3.767


  • Modelling the growth of ZnO thin films by PVD methods and the effects of post-annealing

    Blackwell, S.; Smith, R.; Kenny, S.D.; Walls, J.M.; Sanz-Navarro, C.F. Journal of Physics Condensed Matter; 25 2013. 10.1088/0953-8984/25/13/135002. IF: 2.355


  • Nitrogen-doped graphitic nanoribbons: Synthesis, characterization, and transport

    Ortiz-Medina, J.; García-Betancourt, M.L.; Jia, X.; Martínez-Gordillo, R.; Pelagio-Flores, M.A.; Swanson, D.; Elías, A.L.; Gutiérrez, H.R.; Gracia-Espino, E.; Meunier, V.; Owens, J.; Sumpter, B.G.; Cruz-Silva, E.; Rodríguez-Macías, F.J.; Lõpez-Urías, F.; Muñoz-Sandoval, E.; Dresselhaus, M.S.; Terrones, H.; Terrones, M. Advanced Functional Materials; 23: 3755 - 3762. 2013. 10.1002/adfm.201202947. IF: 9.765


  • Site- and orbital-dependent charge donation and spin manipulation in electron-doped metal phthalocyanines

    Krull, C.; Robles, R.; Mugarza, A.; Gambardella, P. Nature Materials; 12: 337 - 343. 2013. 10.1038/nmat3547. IF: 35.749


  • Surface-induced dechlorination of FeOEP-Cl** on Cu(111)

    Van Vörden, D.; Lange, M.; Schaffert, J.; Cottin, M.C.; Schmuck, M.; Robles, R.; Wende, H.; Bobisch, C.A.; Möller, R. Chemphyschem : a European journal of chemical physics and physical chemistry; 14: 3472 - 3475. 2013. 10.1002/cphc.201300497. IF: 3.349


  • Surface-state engineering for interconnects on H-passivated Si(100)

    Kepenekian, M.; Robles, R.; Joachim, C.; Lorente, N. Nano Letters; 13: 1192 - 1195. 2013. 10.1021/nl304611m. IF: 13.025


  • Surface-supported supramolecular pentamers

    Karan, S.; Wang, Y.; Robles, R.; Lorente, N.; Berndt, R. Journal of the American Chemical Society; 135: 14004 - 14007. 2013. 10.1021/ja405456k. IF: 10.677


  • Tight-binding model and direct-gap/indirect-gap transition in single-layer and multilayer MoS2

    Cappelluti, E.; Roldán, R.; Silva-Guillén, J.A.; Ordejón, P.; Guinea, F. Physical Review B - Condensed Matter and Materials Physics; 88 2013. 10.1103/PhysRevB.88.075409. IF: 3.767


  • Tunneling electron induced rotation of a copper phthalocyanine molecule on Cu(111)

    Schaffert, J.; Cottin, M.C.; Sonntag, A.; Bobisch, C.A.; Möller, R.; Gauyacq, J.-P.; Lorente, N. Physical Review B - Condensed Matter and Materials Physics; 88 2013. 10.1103/PhysRevB.88.075410. IF: 3.767


  • Vibrational transition rule during a through-bond electron transfer process

    Monturet, S.; Kepenekian, M.; Robles, R.; Lorente, N.; Joachim, C. Chemical Physics Letters; 567: 1 - 5. 2013. 10.1016/j.cplett.2013.02.057. IF: 2.145


2012

  • A theoretical rationalization of a total inelastic electron tunneling spectrum: The comparative cases of formate and benzoate on Cu(111)

    Burema, S.R.; Lorente, N.; Bocquet, M.-L. Journal of Chemical Physics; 136 2012. 10.1063/1.4730168.


  • Calculation of core level shifts within DFT using pseudopotentials and localized basis sets

    García-Gil, S.; García, A.; Ordejón, P. European Physical Journal B; 85 2012. 10.1140/epjb/e2012-30334-5.


  • Carbon nanotubes as substrates for molecular spiropyran-based switches

    Malic, E.; Setaro, A.; Bluemmel, P.; Sanz-Navarro, C.F.; Ordejón, P.; Reich, S.; Knorr, A. Journal of Physics Condensed Matter; 24: 394006. 2012. .


  • Dielectric screening in extended systems using the self-consistent Sternheimer equation and localized basis sets

    Hübener, H.; Pérez-Osorio, M.A.; Ordejón, P.; Giustino, F. Physical Review B - Condensed Matter and Materials Physics; 85 2012. 10.1103/PhysRevB.85.245125.


  • Electrochemical ferroelectric switching: Origin of polarization reversal in ultrathin films

    Bristowe, N.C.; Stengel, M.; Littlewood, P.B.; Pruneda, J.M.; Artacho, E. Physical Review B - Condensed Matter and Materials Physics; 85 2012. 10.1103/PhysRevB.85.024106.


  • Electronic and magnetic properties of molecule-metal interfaces: Transition-metal phthalocyanines adsorbed on Ag(100)

    Mugarza, A.; Robles, R.; Krull, C.; Korytár, R.; Lorente, N.; Gambardella, P. Physical Review B - Condensed Matter and Materials Physics; 85 2012. 10.1103/PhysRevB.85.155437.


  • Electroresistance effect in ferroelectric tunnel junctions with symmetric electrodes

    Bilc, D.I.; Novaes, F.D.; Íñiguez, J.; Ordejón, P.; Ghosez, P. ACS Nano; 6: 1473 - 1478. 2012. 10.1021/nn2043324.


  • Energetics and stability of dangling-bond silicon wires on H passivated Si(100)

    Robles, R.; Kepenekian, M.; Monturet, S.; Joachim, C.; Lorente, N. Journal of Physics Condensed Matter; 24 2012. 10.1088/0953-8984/24/44/445004.


  • Excitation of local magnetic moments by tunneling electrons

    Gauyacq, J.-P.; Lorente, N.; Novaes, F.D. Progress in Surface Science; 87: 63 - 107. 2012. 10.1016/j.progsurf.2012.05.003.


  • Insulating behavior of an amorphous graphene membrane

    Van Tuan, D.; Kumar, A.; Roche, S.; Ortmann, F.; Thorpe, M.F.; Ordejon, P. Physical Review B - Condensed Matter and Materials Physics; 86 2012. 10.1103/PhysRevB.86.121408.


  • Lifetime of magnetic excitations in supported ferromagnetic and antiferromagnetic spin-12 Heisenberg chains

    Gauyacq, J.P.; Lorente, N. Physical Review B - Condensed Matter and Materials Physics; 85 2012. 10.1103/PhysRevB.85.115420.


  • Many-body effects in magnetic inelastic electron tunneling spectroscopy

    Korytár, R.; Lorente, N.; Gauyacq, J.-P. Physical Review B - Condensed Matter and Materials Physics; 85 2012. 10.1103/PhysRevB.85.125434.


  • Native defects in hybrid C/BN nanostructures by density functional theory calculations

    Pruneda, J.M. Physical Review B - Condensed Matter and Materials Physics; 85 2012. 10.1103/PhysRevB.85.045422.


  • Performance of local orbital basis sets in the self-consistent Sternheimer method for dielectric matrices of extended systems

    Hubene, H.; Perez-Osorio, M.A.; Ordejon, P.; Giustino, F. European Physical Journal B; 85: 321. 2012. .


  • Spin doping of individual molecules by using single-atom manipulation

    Robles, R.; Lorente, N.; Isshiki, H.; Liu, J.; Katoh, K.; Breedlove, B.K.; Yamashita, M.; Komeda, T. Nano Letters; 12: 3609 - 3612. 2012. 10.1021/nl301301e.


  • Y:BaZrO 3 perovskite compounds I: DFT study on the unprotonated and protonated local structures

    Cammarata, A.; Ordejón, P.; Emanuele, A.; Duca, D. Chemistry - An Asian Journal; 7: 1827 - 1837. 2012. 10.1002/asia.201100974.


2011

  • An efficient implementation of a QM-MM method in SIESTA

    Sanz-Navarro, C.F.; Grima, R.; García, A.; Bea, E.A.; Soba, A.; Cela, J.M.; Ordejón, P. Theoretical Chemistry Accounts; 128: 825 - 833. 2011. 10.1007/s00214-010-0816-5.


  • Cis-dicarbonyl binding at cobalt and iron porphyrins with saddle-shape conformation

    Seufert, K.; Bocquet, M.-L.; Auwärter, W.; Weber-Bargioni, A.; Reichert, J.; Lorente, N.; Barth, J.V. Nature Chemistry; 3: 114 - 119. 2011. 10.1038/nchem.956.


  • Excitation of spin waves by tunneling electrons in ferromagnetic and antiferromagnetic spin-12 Heisenberg chains

    Gauyacq, J.P.; Lorente, N. Physical Review B - Condensed Matter and Materials Physics; 83 2011. 10.1103/PhysRevB.83.035418.


  • Magnetic excitation by tunneling electrons of frustrated ferromagnetic spin-12 chains and rings

    Gauyacq, J.P.; Lorente, N. Physical Review B - Condensed Matter and Materials Physics; 84 2011. 10.1103/PhysRevB.84.085415.


  • Magnetism-dependent transport phenomena in hydrogenated graphene: From spin-splitting to localization effects

    Leconte, N.; Soriano, D.; Roche, S.; Ordejon, P.; Charlier, J.-C.; Palacios, J.J. ACS Nano; 5: 3987 - 3992. 2011. 10.1021/nn200558d.


  • Magnetoresistance and magnetic ordering fingerprints in hydrogenated graphene

    Soriano, D.; Leconte, N.; Ordejón, P.; Charlier, J.C.; Palacios, J.-J.; Roche, S. Physical Review Letters; 107 2011. 10.1103/PhysRevLett.107.016602.


  • Modulation of surface charge transfer through competing long-range repulsive versus short-range attractive interactions

    Fraxedas, J.; García-Gil, S.; Monturet, S.; Lorente, N.; Fernández-Torrente, I.; Franke, K.J.; Pascual, J.I.; Vollmer, A.; Blum, R.-P.; Koch, N.; Ordejón, P. Journal of Physical Chemistry C; 115: 18640 - 18648. 2011. 10.1021/jp2050838.


  • Multi-orbital non-crossing approximation from maximally localized Wannier functions: The Kondo signature of copper phthalocyanine on Ag(100)

    Korytr, R.; Lorente, N. Journal of Physics Condensed Matter; 23 2011. 10.1088/0953-8984/23/35/355009.


  • Observation and electric current control of a local spin in a single-molecule magnet

    Komeda, T.; Isshiki, H.; Liu, J.; Zhang, Y.F.; Lorente, N.; Katoh, K.; Breedlove, B.K.; Yamashita, M. Nature Communications; 2 2011. 10.1038/ncomms1210.


  • Oxygen surface functionalization of graphene nanoribbons for transport gap engineering

    Cresti, A.; Lopez-Bezanilla, A.; Ordejón, P.; Roche, S. ACS Nano; 5: 9271 - 9277. 2011. 10.1021/nn203573y.


  • Quantum transport in chemically modified two-dimensional graphene: From minimal conductivity to Anderson localization

    Leconte, N.; Lherbier, A.; Varchon, F.; Ordejon, P.; Roche, S.; Charlier, J.-C. Physical Review B - Condensed Matter and Materials Physics; 84 2011. 10.1103/PhysRevB.84.235420.


  • Spin coupling and relaxation inside molecule-metal contacts.

    Mugarza, A.; Krull, C.; Robles, R.; Stepanow, S.; Ceballos, G.; Gambardella, P. Nature Communications; 2 2011. 10.1038/ncomms1497.


  • Structural, dynamical, and electronic transport properties of modified DNA duplexes containing size-expanded nucleobases

    Blas, J.R.; Huertas, O.; Tabares, C.; Sumpter, B.G.; Fuentes-Cabrera, M.; Orozco, M.; Ordejón, P.; Luque, F.J. The journal of physical chemistry, A, Molecules, spectroscopy, kinetics, environment & general theory; 115: 11344 - 11354. 2011. 10.1021/jp205122c.


  • Theoretical study of magnetic moments induced by defects at the SiC(110) surface

    Poissier, A.; Lorente, N.; Yndurain, F. Physical Review B - Condensed Matter and Materials Physics; 83 2011. 10.1103/PhysRevB.83.035322.


2010

  • Band selection and disentanglement using maximally localized Wannier functions: The cases of Co impurities in bulk copper and the Cu(111) surface

    Korytár, R.; Pruneda, M.; Junquera, J.; Ordejón, P.; Lorente, N. Journal of Physics Condensed Matter; 22 2010. 10.1088/0953-8984/22/38/385601.


  • Damaging graphene with ozone treatment: A chemically tunable metal - Insulator transition

    Leconte, N.; Moser, J.; Ordejón, P.; Tao, H.; Lherbier, A.; Bachtold, A.; Alsina, F.; Sotomayor Torres, C.M.; Charlier, J.-C.; Roche, S. ACS Nano; 4: 4033 - 4038. 2010. 10.1021/nn100537z.


  • Density-wave instability in α- ( BEDT-TTF)2KHg(SCN) 4 studied by x-ray diffuse scattering and by first-principles calculations

    Foury-Leylekian, P.; Pouget, J.-P.; Lee, Y.-J.; Nieminen, R.M.; Ordejón, P.; Canadell, E. Physical Review B - Condensed Matter and Materials Physics; 82 2010. 10.1103/PhysRevB.82.134116.


  • Electronic transport between graphene layers covalently connected by carbon nanotubes

    Novaes, F.D.; Rurali, R.; Ordejón, P. ACS Nano; 4: 7596 - 7602. 2010. 10.1021/nn102206n.


  • Graphene on Ru(0001): Contact formation and chemical reactivity on the atomic scale

    Altenburg, S.J.; Kröger, J.; Wang, B.; Bocquet, M.L.; Lorente, N.; Berndt, R. Physical Review Letters; 105 2010. 10.1103/PhysRevLett.105.236101.


  • Growth and Structure of Self-assembled Monolayers of a TTF Derivative on Au(111)

    Urban, C.; Écija, D.; Wang, Y.; Trelka, M.; Preda, I.; Vollmer, A.; Lorente, N.; Arnau, A.; Alcamí, M.; Soriano, L.; Martín, N.; Martín, F.; Otero, R.; Gallego, J.M.; Miranda, R. Journal of Physical Chemistry C; 114: 6503 - 6510. 2010. 10.1021/jp911839b.


  • Magnetic transitions induced by tunneling electrons in individual adsorbed M -phthalocyanine molecules (M=Fe and Co)

    Gauyacq, J.-P.; Novaes, F.D.; Lorente, N. Physical Review B - Condensed Matter and Materials Physics; 81 2010. 10.1103/PhysRevB.81.165423.


  • Mixed-valency signature in vibrational inelastic electron tunneling spectroscopy

    Alducin, M.; Sánchez-Portal, D.; Arnau, A.; Lorente, N. Physical Review Letters; 104 2010. 10.1103/PhysRevLett.104.136101.


  • Orbital specific chirality and homochiral self-assembly of achiral molecules induced by charge transfer and spontaneous symmetry breaking

    Mugarza, A.; Lorente, N.; Ordejón, P.; Krull, C.; Stepanow, S.; Bocquet, M.-L.; Fraxedas, J.; Ceballos, G.; Gambardella, P. Physical Review Letters; 105 2010. 10.1103/PhysRevLett.105.115702.


  • Origin of half-semimetallicity induced at interfaces of C-BN heterostructures

    Pruneda, J.M. Physical Review B - Condensed Matter and Materials Physics; 81 2010. 10.1103/PhysRevB.81.161409.


  • Preface: Phys. stat. sol. (c) 7/11-12

    Correia, A.; Sáenz, J.J.; Ordejon, P.; Roche, S. Physica Status Solidi (C) Current Topics in Solid State Physics; 7: 2593 - 2595. 2010. 10.1002/pssc.201060100.


  • Quenching of magnetic excitations in single adsorbates at surfaces: Mn on CuN/Cu(100)

    Novaes, F.D.; Lorente, N.; Gauyacq, J.-P. Physical Review B - Condensed Matter and Materials Physics; 82 2010. 10.1103/PhysRevB.82.155401.


  • Real-time TD-DFT simulations in dye sensitized solar cells: The electronic absorption spectrum of alizarin supported on TiO2 nanoclusters

    Sánchez-De-Armas, R.; Oviedo López, J.; San-Miguel, M.A.; Sanz, J.F.; Ordejón, P.; Pruneda, M. Journal of Chemical Theory and Computation; 6: 2856 - 2865. 2010. 10.1021/ct100289t.


  • Role of molecular electronic structure in inelastic electron tunneling spectroscopy: O2 on Ag(110)

    Monturet, S.; Alducin, M.; Lorente, N. Physical Review B - Condensed Matter and Materials Physics; 82 2010. 10.1103/PhysRevB.82.085447.


2009

  • Efficient spin transitions in inelastic electron tunneling spectroscopy

    Lorente, N.; Gauyacq, J.-P. Physical Review Letters; 103 2009. 10.1103/PhysRevLett.103.176601.


  • He-LiF surface interaction potential from fast atom diffraction

    Schüller, A.; Winter, H.; Gravielle, M.S.; Pruneda, J.M.; Miraglia, J.E. PHYSICAL REVIEW A; 80 2009. 10.1103/PhysRevA.80.062903.


  • Nonadiabatic wavepacket dynamics: K-space formulation

    Pruneda, J.M.; Souza, I. Physical Review B - Condensed Matter and Materials Physics; 79 2009. 10.1103/PhysRevB.79.045127.


  • Optimal strictly localized basis sets for noble metal surfaces

    García-Gil, S.; García, A.; Lorente, N.; Ordejón, P. Physical Review B - Condensed Matter and Materials Physics; 79 2009. 10.1103/PhysRevB.79.075441.


  • Physica Status Solidi C: Preface

    Correia, A.; Sáenz, J.J.; Ordejón, P. Physica Status Solidi (C) Current Topics in Solid State Physics; 6: 2093 - 2095. 2009. 10.1002/pssc.200960073.


  • Probing the proton location in a water bilayer on Pd (111) by inelastic spectroscopy simulations

    Bocquet, M.-L.; Lorente, N. Journal of Chemical Physics; 130 2009. 10.1063/1.3089824.


  • Selective scanning tunnelling microscope electron-induced reactions of single biphenyl molecules on a Si(100) surface

    Riedel, D.; Bocquet, M.-L.; Lesnard, H.; Lastapis, M.; Lorente, N.; Sonnet, P.; Dujardin, G. Journal of the American Chemical Society; 131: 7344 - 7352. 2009. 10.1021/ja8101133.


  • Solid-state physics: Lost magnetic moments

    Korytár, R.; Lorente, N. Nature; 458: 1123 - 1124. 2009. 10.1038/4581123a.


  • Tunneling spectroscopy in core/shell structured Fe/MgO nanospheres

    Martínez-Boubeta, C.; Balcells, Li.; Monty, C.; Ordejon, P.; Martínez, B. Applied Physics Letters; 94 2009. 10.1063/1.3080657.


2008

  • Adsorption of N2O on Cu(100): A combined scanning tunneling microscopy and density functional theory study

    Franke, K.J.; Fernández-Torrente, I.; Pascual, J.I.; Lorente, N. Physical Chemistry Chemical Physics; 10: 1640 - 1647. 2008. 10.1039/b716952c.


  • Band bending and quasi-2deg in the metallized β-SiC(001) surface

    Rurali, R.; Wachowicz, E.; Hyldgaard, P.; Ordejón, P. Physica Status Solidi - Rapid Research Letetrs; 2: 218 - 220. 2008. 10.1002/pssr.200802166.


  • Creating pseudo-Kondo resonances by field-induced diffusion of atomic hydrogen

    Hofer, W.A.; Teobaldi, G.; Lorente, N. Nanotechnology; 19 2008. 10.1088/0957-4484/19/30/305701.


  • Dynamic Jahn-Teller effect in electronic transport through single C 60 molecules

    Frederiksen, T.; Franke, K.J.; Arnau, A.; Schulze, G.; Pascual, J.I.; Lorente, N. Physical Review B - Condensed Matter and Materials Physics; 78 2008. 10.1103/PhysRevB.78.233401.


  • Formation of dispersive hybrid bands at an organic-metal interface

    Gonzalez-Lakunza, N.; Fernández-Torrente, I.; Franke, K.J.; Lorente, N.; Arnau, A.; Pascual, J.I. Physical Review Letters; 100 2008. 10.1103/PhysRevLett.100.156805.


  • Inelastic effects in electron transport studied with wave packet propagation

    Monturet, S.; Lorente, N. Physical Review B - Condensed Matter and Materials Physics; 78 2008. 10.1103/PhysRevB.78.035445.


  • Reducing the molecule-substrate coupling in C60-based nanostructures by molecular interactions

    Franke, K.J.; Schulze, G.; Henningsen, N.; Fernández-Torrente, I.; Pascual, J.I.; Zarwell, S.; Rück-Braun, K.; Cobian, M.; Lorente, N. Physical Review Letters; 100 2008. 10.1103/PhysRevLett.100.036807.


  • The SIESTA method; Developments and applicability

    Artacho, E.; Anglada, E.; Diéguez, O.; Gale, J.D.; García, A.; Junquera, J.; Martin, R.M.; Ordejón, P.; Pruneda, J.M.; Sánchez-Portal, D.; Soler, J.M. Journal of Physics Condensed Matter; 20 2008. 10.1088/0953-8984/20/6/064208.


  • Theoretical study of benzene and pyridine STM-induced reactions on copper surfaces

    Lesnard, H.; Lorente, N.; Bocquet, M.-L. Journal of Physics Condensed Matter; 20 2008. 10.1088/0953-8984/20/22/224012.


  • Unified description of inelastic propensity rules for electron transport through nanoscale junctions

    Paulsson, M.; Frederiksen, T.; Ueba, H.; Lorente, N.; Brandbyge, M. Physical Review Letters; 100 2008. 10.1103/PhysRevLett.100.226604.


2007

  • Chemisorption of sulfur and sulfur-based simple molecules on Au(111)

    Gonzalez-Lakunza, N.; Lorente, N.; Arnau, A. Journal of Physical Chemistry C; 111: 12383 - 12390. 2007. 10.1021/jp0726586.


  • GaS and InSe equations of state from single crystal diffraction

    J. Pellicer-Porres; E. Machado-Charry; A. Segura; S. Gilliland; E. Canadell; P. Ordejón; A. Polian; P. Munsch; A. Chevy y N. Guignot Physica Status Solidi (B): Basic Research; 2007. .


  • Including the probe tip in theoretical models of inelastic scanning tunneling spectroscopy: CO on Cu(100)

    Teobaldi, G.; Peñalba, M.; Arnau, A.; Lorente, N.; Hofer, W.A. Physical Review B - Condensed Matter and Materials Physics; 76 2007. 10.1103/PhysRevB.76.235407.


  • Interaction of copper organometallic precursors with barrier layers of Ti, Ta and W and their nitrides: a first-principles molecular dynamics study

    E. Machado; M. Kaczmarski; B. Braida; P. Ordejón; D. Garg; J. Norman; H. Cheng Journal of Molecular Modeling; 2007. .


  • Long-range repulsive interaction between molecules on a metal surface induced by charge transfer

    Fernandez-Torrente, I.; Monturet, S.; Franke, K.J.; Fraxedas, J.; Lorente, N.; Pascual, J.I. Physical Review Letters; 99 2007. 10.1103/PhysRevLett.99.176103.


  • Resistive and rectifying effects of pulling gold atoms at thiol-gold nanocontacts

    R. J. C. Batista; P. Ordejón; H. Chacham; E. Artacho Physical Review B; 2007. .


  • The Calculation of Free-Energiesin Semiconductors: Defects, Transitionsand Phase Diagrams

    E. R. Hernández; A. Antonelli; L. Colombo; P. Ordejón Topics in Applied Physics; 104: 115 - 140. 2007. .


  • Transport measurements under pressure in III¿IV layered semiconductors

    A. Segura; D. Errandonea; D. Martínez García; F. J. Manjón; A. Chevy; G. Tobías; P. Ordejón; E. Canadell Physica Status Solidi (B): Basic Research; 244: 162 - 168. 2007. .


2006

  • Electron transport via local polarons at interface atoms

    Berthe, M.; Urbieta, A.; Perdigão, L.; Grandidier, B.; Deresmes, D.; Delerue, C.; Stiévenard, D.; Rurali, R.; Lorente, N.; Magaud, L.; Ordejón, P. Physical Review Letters; 97 2006. 10.1103/PhysRevLett.97.206801.


  • Methylthiolate adsorption on Au(1 1 1): Energetics, vibrational modes and STM imaging

    Gonzalez, N.; Lorente, N.; Arnau, A. Surface Science; 600: 4039 - 4043. 2006. 10.1016/j.susc.2006.01.119.


2005

  • First-principles study of structural, elastic, and bonding properties of pyrochlores

    J.M. Pruneda; Emilio Artacho Physical Review B - Condensed Matter and Materials Physics; 2005. .


  • Self-doped titanium oxide thin films for efficient visible light photocatalysis: An example: Nonylphenol photodegradation

    Justicia, I.; Garcia, G.; Vázquez, L.; Santiso, J.; Ordejón, P.; Battiston, G.; Gerbasi, R.; Figueras, A. Sensors and Actuators, B: Chemical; 109: 52 - 56. 2005. 10.1016/j.snb.2005.03.021.


2004

  • Intrinsic point defects and volume swelling in ZrSiO4 under irradiation

    J. M. Pruneda; T. D. Archer; Emilio Artacho Physical Review B - Condensed Matter and Materials Physics; 2004. .


  • Short-range repulsive interatomic interactions in energetic processes in solids

    J. M. Pruneda; Emilio Artacho Physical Review B - Condensed Matter and Materials Physics; 2004. .