Dresden 2011 – scientific programme
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O: Fachverband Oberflächenphysik
O 74: Focussed session: Theory and computation of electronic structure: new frontiers VI (jointly with HL, DS)
O 74.2: Talk
Thursday, March 17, 2011, 15:15–15:30, TRE Phy
Electronic excitations from a perturbative LDA+GdW approach — •Michael Rohlfing — Fachbereich Physik, Universität Osnabrück, Germany
We discuss an efficient approach to excited electronic states within ab-initio many-body perturbation theory (MBPT). Quasiparticle corrections to density-functional theory result from the difference between metallic and non-metallic dielectric screening. They are evaluated as a small perturbation to the DFT-LDA band structure, rather than fully calculating the self energy and evaluating its difference from the exchange-correlation potential. The dielectric screening is desribed by a model, which applies to bulk crystals, as well as, to systems of reduced dimension, like molecules, surfaces, interfaces, and more. The approach also describes electron-hole interaction. The resulting electronic and optical spectra are slightly less accurate but much faster to calculate than a full MBPT calculation. We discuss results for bulk silicon and argon, for the Si(111)-(2×1) surface, the SiH4 molecule, an argon-aluminum interface, and liquid argon.
[1] M. Rohlfing, Phys. Rev. B 82, 205127 (2010).