Dresden 2006 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 15: III-V semiconductors II
HL 15.2: Vortrag
Dienstag, 28. März 2006, 11:15–11:30, POT 51
Combining quasiparticle energy calculations with exact-exchange density-functional theory: the bandgap of InN — •Patrick Rinke1, Abdallah Qteish2, Jörg Neugebauer1,3, and Matthias Scheffler1 — 1Fritz-Haber-Institut der MPG, Berlin — 2Department of Physics, Yarmouk University, Irbid - Jordan — 3MPI für Eisenforschung, Düsseldorf
Amongst the group-III-nitrides InN assumes a special place because the magnitude of its bandgap is still controversial. If one believes density-functional theory (DFT) calculations in the local-density approximation (LDA) or LDA based quasiparticle energy calculations in the G0W0 approximation InN should be metallic. Recent experiments [1,2], however, place the band gap between 0.7 and 1.0 eV, significantly lower than previously thought. For GaN and II-VI compounds we have shown that DFT in the exact-exchange (EXX) approach gives an improved description of the d-electron hybridization compared to the LDA. In combination with G0W0 calculations we achieve very good agreement with experiment for the band gaps of these compounds [3]. For InN the EXX calculations yield a semiconductor with a band gap of 0.8 eV in the zincblend phase [4] and 1.0 eV for wurtzite. In contrast to GaN the G0W0 corrections are negative and lower the band gap to 0.5 eV and 0.7 eV, respectively - in very good agreement with the new experimental data.
[1] J. Wu et al., Appl. Phys. Lett. 80, 3967 (2002)
[2] T. Takachi et al., Appl. Phys. Lett. 81, 1246 (2002)
[3] P. Rinke et al., New J. Phys. 7, 126 (2005)
[4] A. Qteish et al., Phys. Rev. B 72, 155317 (2005)