Events

Theoretical Spectroscopy of Low Dimensional Systems

November 11, 2009 at 2pm/Pfizer Hall - Mb-23 Harvard University 12 Oxford Street Cambridge

Angel Rubio
Universidad del Pais Vasco UPV/EHU and Centro Mixto CSIC-UPV/EHU

abstract:
There has been much progress in the synthesis and characterization of nanostructures however, there remain immense challenges in understanding their properties and interactions with external probes in order to realize their tremendous potential for applications (molecular electronics, nanoscale opto-electronic devices, light harvesting and emitting nanostructures). In this talk I will review the recent advances within density-functional based schemes to describe the excite state properties of low-dimensional structures (semiconducting nanostructures and biomolecules) including both electron and ionic degrees of freedom. We will address both the linear and non-linear response regimes. We will describe a new method to address the electron-ion dynamics within the Ehrenfest scheme where no explicit orthogonalization is necessary and we can increase of the time step while keeping the system close to the Born-Oppenheimer surface. The method is easily implemented and scales very well with the system size. Applications to the excited state dynamics in some organic molecules will be used as test cases to illustrate the performance of the approach. In particular we will show the effect of electron-hole attraction in those systems. Pros and cons of present functionals will be highlighted and provide insight in how to overcome those limitations by using many-body perturbation theory (i.e. GW based self-energy approaches including excitonic effects at the Bethe-Salpeter level). The present developments constitute a basic ingredient for the development of the European Theoretical Spectroscopy Facility.

Work done in collaboration with A. Castro, M. Marques, X.
Andrade, J.L Alonso, Pablo Echenique, L. Wirtz, A. Marini, M.
Gruning, C. Rozzi, D. Varsano and E.K.U. Gross.

bio:
Angel Rubio is a Professor of Condensed Matter Physics in the Department of Materials of the Faculty of Chemistry in the Basque Country University (UPV/EHU), Scientific Vicepresident of the European Theoretical Spectroscopy Facility, and Distinguished Visiting Scientist at the Fritz Haber Institute der Max-Planck-Gesellschaft, Berlin . His research activity in the fields of theory and modeling of electronic and structural properties in condensed matter and on developing novel theoretical tools and computational codes to investigate the electronic response of solids and nanostructures to external electromagnetic fields is internationally recognized and he hasreceived numerous honors and awards. Among them we would like to mention National Prize for the best Spanish undergraduate student of Physics (1989), faculty honor prize for the best PhD thesis in Physics (1992), Royal Spanish Physical Society Prize “Outstanding young researchers” (1992); Fulbright Fellow (1993); 2001 JSPS Invitation Fellow Program for Research in Japan; 2004 Sir Allan Sewell Fellowship School of Science, Griffith University, Australia; 2004 Fellow of the American Physical Society: Materials Science Division; 2005 Friedrich Wilhelm Bessel Research Award, Humboldt Foundation, Germany; DuPond Prize on Science, 2006. Rubio has an excellent publication record (Hirsch index 52). He is the Editor of three books two about nanotechnologies.