04.02.2014 Electronic Excitation of Condensed Matter: Electrons, holes, excitons, and their ab-initio description

Prof. Dr. Michael Rohlfing, University of Münster

Date: Tuesday, 11.02.2014, 13:15 h
Location: Department of Chemistry, Hans-Meerwein-Straße 4 (Lahnberge), seminar room E4/4326

Joint Theoretical Chemistry- and RTG-Seminar

Abstract

Many properties of condensed matter (e. g. optical spectra, electronic transport, etc.) are determined by excited electronic states (in particular by the electronic band structure and by electron-hole pair excitations, i. e. excitons). The systematic description of these states can be achieved by ab-initio many-body perturbation theory, in particular by the GW method and the Bethe-Salpeter equation. In here the concept of non-local dielectric screening plays a particular role. The numerical evaluation of these concepts contributes to our understanding of the electronic structure of many systems, especially on the atomic length scale and in reduced dimensions.

In the talk I will discuss the key elements of the theory, present the key properties of the involved physical quantities, and discuss a number of prototypical systems. Examples are (among many others) clean semiconductor surfaces, like Si(001)-(2x1), Si(001)-c(4x2), Si(111)-(2x1) oder Ge(111)-(2x1), and molecular adsorbates (C₂H₄, TTF) on Si(001).