Regensburg 2004 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 17: II-VI Halbleiter I

HL 17.8: Vortrag

Dienstag, 9. März 2004, 12:00–12:15, H14

Exact-Exchange-Based Quasiparticle Calculations of II-VI Compounds — •Patrick Rinke¹, Abdallah Qteish², Jörg Neugebauer³, and Matthias Scheffler¹ — ¹Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin — ²Department of Physics, Yarmouk University, Irbid - Jordan — ³Dekanat Physik, Universität Paderborn

We present ab initio electronic structure calculations for the II-VI compounds ZnO, ZnS and ZnSe in the zinc-blende structure. In this context, the GW-approximation to the self-energy has successfully been applied to a wide range of materials. The presence of the shallow semicore d-electrons of Zn, however, poses a conceptual as well as computational challenge. Previous quasiparticle calculations for ZnS and ZnSe have in common that GW was applied as a perturbation to a density-functional theory (DFT) calculation within either the local-density or a generalised gradient approximation, but differ crucially in the pseudopotentials used. Here we present DFT calculations in the exact-exchange (EXX) formalism, which gives good agreement with quasiparticle calculations and also with experiment for standard semiconductors [1]. We apply the EXX approximation consistently using the newly developed approach of KLI-pseudopotentials. Furthermore we use the EXX energies and wavefunctions as input for a GW calculation to examine the role of the 3d-electrons and the p - d repulsion.

1. W. G. Aulbur, M. Städele and A. Görling, Phys. Rev. B 62 7121 (2000)