Theory and Simulation Group

Group Leader: Pablo Ordejón

Main Research Lines

  • Development of theoretical methods, numerical algorithms and simulation tools
  • First Principles simulations at the nanoscale
  • Novel physical properties in 2D materials

One of the highlights of 2015 has been the birth of the MaX Center (, one of the eight ‘European Centers of Excellence for HPC applications’ supported by the EU under its H2020 e-INFRA-2015 call. MaX supports developers and end users of advanced applications for materials simulations, design and discovery, and works at the frontiers of the current and future High Performance Computing (HPC) technologies. It gathers leading developers and users of materials applications, together with top experts in HPC. It is based on the collaboration of 13 teams, including 5 research teams, like the ICN2 Theory and Simulation Group, that will focus on enhancing the capabilities of the SIESTA package, and develop new methodologies for industrial applications of simulation tools in materials science.

The group also has a leading role in NFFA-Europe (, a project funded by the EU H2020- INFRAIA-2014-2015 call “Integrating and opening existing national and regional research infrastructures of European interest”. 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” that offers access computational support to experimental users’ projects.

On the scientific side, during 2015 we have pushed two new important research lines in the group:

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, by developing new tools and methodologies. In particular, we are exploring the thermal transport properties of 2D materials, which have revealed unusual behaviors (as compared to bulk systems), leading to unexpected intriguing features of large potential impact in several front-edge or emerging nanotechnologies (e.g. heat management in nanodevices, thermoelectric energy conversion, or manipulation of lattice heat to engineer phononic devices).

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

With respect of previously existing research lines, we have made strong advances on:

Understanding the properties in 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 examples of our activity in 2D materials during 2015.

Theoretical modelling of photocatalysis: Heterogeneous photocatalysis has an important impact in many fields, like solar energy, the production of fuels and chemicals, and environmental remediation. We use many-body quasiparticle GW calculations to compute the level alignment of the adsorbate and substrate levels of prototypical photocatalytic interfaces (water, methanol, catechol on rutile or anatase TiO2). We have shown that our calculations provide a quantitative in-depth interpretation of ultraviolet photoemission spectroscopy (UPS) and two-photon photoemission (2PP) spectroscopy experiments. 

Group Leader

Pablo Ordejón

CSIC Research Professor

Prof Ordejón earned his BSc in Physics (1987) and PhD in Science (1992) at the Universidad Autónoma de Madrid (Spain). 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 of the Consejo Superior de Investigaciones Científicas (CSIC). In 2007 he moved to CIN2 (now ICN2), where he is currently CSIC Research Profesor. Since July 2012, he has served as Director of ICN2, where he also leads the Theory and Simulation Research Group.

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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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