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HL: Halbleiterphysik

HL 11: II-VI Halbleiter I

HL 11.2: Vortrag

Freitag, 4. März 2005, 15:15–15:30, TU P164

Combining quasiparticle energy calculations with exact-exchange density-functional theory for II-VI compounds and group-III-nitrides — •Patrick Rinke¹, Abdallah Qteish², Jörg Neugebauer³, Christoph Freysoldt¹, and Matthias Scheffler¹ — ¹Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin — ²Department of Physics, Yarmouk University, Irbid - Jordan — ³Department of Theoretical Physics, University of Paderborn, Paderborn

We present a systematic ab initio study of the electronic structure for selected II-VI compounds and group III nitrides in the zinc-blende structure with special emphasis on the role played by the semicore d-electrons. We show that applying density-functional theory (DFT) in the exact-exchange (EXX) approach [1] leads to an improved description of the d-electron hybridisation compared to the local-density approximation (LDA). Moreover we find that it is essential to use the newly developed EXX pseudopotentials [2] in order to treat core-valence exchange consistenly.

In combination with quasiparticle energy calculations in the GW approximation we achieve very good agreement with available photoemission data. Since the DFT energies and wavefunctions serve as input for the GW calculation we conclude that for these materials EXX constitutes the better groundstate.

[1] M. Städele et al, Phys. Rev. Lett. 79 2089 (1997)

[2] M. Moukara et al, J. Phys.: Condens. Matter 12 6783 (2000)