AVS 51st International Symposium
    Semiconductors Tuesday Sessions
       Session SC-TuP

Paper SC-TuP6
Exact-Exchange-Based Quasiparticle Calculations of II-VI Compounds and Group III Nitrides

Tuesday, November 16, 2004, 4:00 pm, Room Exhibit Hall B

Session: Poster Session
Presenter: P. Rinke, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Germany
Authors: P. Rinke, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Germany
A. Qteish, Yarmouk University, Jordan
J. Neugebauer, University of Paderborn, Germany
M. Scheffler, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Germany
Correspondent: Click to Email
We present a systematic ab initio study of the electronic structure for a wide range of II-VI compounds and group III nitrides in the zinc-blende structure. The challenge from a computational point of view is to capture the exchange-correlation effects arising from the shallow semicore d-electrons of the cation, which we explicitly treat as valence states in our pseudopotential approach. In order to correctly describe the dominant exchange interaction we apply density-functional theory (DFT) in the exact-exchange (EXX) approximation. Although the EXX Kohn-Sham bandstructure compares well with experiment for standard semiconductors@footnote 1@ the bandstructure as measured by photoemission is a property of the excited system. We therefore apply many-body perturbation theory in the GW approximation to the EXX groundstate. The hirarchy of our approach allows us to systematically investigate the role of exchange and correlation in these materials from first principles. Our results show that it is crucial to treat exchange and correlation on the same footing at every stage. To achieve this in our EXX calculations we employ the newly developed EXX-pseudopotentials@footnote 2@. Furthermore we obtain GW bandstructures in very good agreement with existing all-electron GW calculations. Our results indicate that, in contrast to common believe, a pseudopotential approach including only the d-electrons of the semicore shell in question, is sufficient to accurately describe the electronic structure if treated in the EXX+GW formalism. @FootnoteText@ @footnote 1@ W. G. Aulbur et al, Phys. Rev. B 62, 7121 (2000)@footnote 2@ M. Moukara et al, J. Phys.: Condens. Matter 12, 6783 (2000) .