Theory and Simulation Group

Group Leader: Pablo Ordejón

Main Research Lines

  • Development of theoretical methods, numerical algorithms and simulation tools
  • Codes: SIESTA and TRANSIESTA
  • First-principles simulations at the nanoscale
  • Novel physical properties in 2D materials

Most of the research carried out by the group in 2016 has gravitated around the MaX Centre (www.max-centre.eu), one of the eight European Centres of Excellence in HPC Applications supported by the EU under its 2105 H2020 e-infrastructure funding programme. 

MaX supports developers and end users of advanced applications for materials simulations, design and discovery, and works at the frontiers of current and future high performance computing (HPC) technologies. It brings together leading developers and users of materials applications, together with top experts in HPC. It is based on the collaboration of 13 teams, including five research groups, like the ICN2 Theory and Simulation Group, which will focus on enhancing the capabilities of the SIESTA package and develop new methodologies for industrial applications of simulation tools in materials science.

Considerable effort has been devoted to improve the modularity and efficiency of the SIESTA and TRANSIESTA codes. The first release of the SIESTA code under a GPL license at the beginning of the year  was an important milestone in 2016, as was the TranSiesta/TBTrans School organised at the ICN2, which was a great opportunity to present some major recent developments in the tools developed by the group. The release of the spin-orbit implementation and a first operative version of the Density Functional Perturbation Theory within the code are also among the group’s achievements in 2016.

The group has continued its participation in NFFAEurope (www.nffa.eu), a project funded under the H2020-INFRAIA-2014-2015 call “Integrating and opening existing national and regional research infrastructures of European interest”. The NFFA (Nanoscience Foundries and Fine Analysis) is a platform for interdisciplinary research at the nanoscale, in which the Theory and Simulation Group participates as an “installation” offering access to computational support for experimental user projects.

On the science side of things, in 2016 we made progress along two new important research lines:

Thermal transport at the nanoscale: Taking advantage of the expertise of visiting Professor Colombo on thermal transport at the nanoscale, and coordinated with theoretical and experimental collaborators, the group has moved forward in this exciting topic, developing new tools and methodologies. In particular, we are exploring the thermal transport properties of 2D materials, which have revealed unusual behaviours (as compared to bulk systems), leading to unexpected intriguing features with significant potential for various front-edge and emerging nanotechnologies (e.g. heat management in nanodevices, thermoelectric energy conversion or the manipulation of lattice heat to engineer phononic devices). Within the MaX Centre, and in the context of an industrial collaboration, we have also focused on techniques to study thermal properties in nanofluids, which potential impact on energy storage.

Magnetic properties at the nanoscale, with new developments in SIESTA that make the study of systems with strong spin-orbit effects (including topological insulators) possible, as well as the study of magnetic anisotropies in thin films and other nanostructured materials. We have used the working versions in our study of hybrid organic-inorganic perovskites, layered graphene-based magnetic nanostructures and topological insulators. These materials are very promising in the development of spin-based applications, which are of great interest at the ICN2 as a whole. 

With respect to the existing research lines, we have made strong advances on:

Understanding the properties of 2D materials: Vertical stacks of transition metal dichalcogenides; grain boundaries and 1D polar discontinuities; graphene-based devices for DNA sequencing; and insights in the superconducting transition from STM experiments are all examples of our activities in 2D materials during 2016. 

Understanding nanostructured oxides: In collaboration with experimental colleagues in Argentina, we studied the mechanisms contributing to oxygen reduction reactions in manganites (La(1-x)SrxMnO3), identifying an increased oxygen vacancy concentration close to the surfaces that causes significant ionic conduction and enables the use of these nanostructured materials in solid oxide fuel cells in the “intermediate” temperature range. In addition to this collaboration, and motivated by the MaX Centre, we have established a new research collaboration with industry to advance oxygen diffusion in materials for sensor applications, which will run over the coming years.

 

Group Leader

Pablo Ordejón

CSIC Research Professor

Prof Ordejón earned his degree in Physics (1987) and PhD in Science (1992) at the Universidad Autónoma de Madrid. He worked as a postdoctoral researcher at the University of Illinois at Urbana-Champaign (USA) from 1992 to 1995, and as assistant professor at the Universidad de Oviedo from 1995 to 1999. In 1999 he obtained a research staff position at the Institut de Ciència de Materials de Barcelona (ICMAB-CSIC). In 2007 he moved to CIN2 (now ICN2) as the leader of the Theory and Simulation Group, where he is currently a CSIC Research Professor. Since July 2012 he has served as Director of the ICN2.

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Highlighted Publication

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 (2016)

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