Regensburg 2016 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 84: Novel Functional Materials I
HL 84.6: Vortrag
Donnerstag, 10. März 2016, 16:45–17:00, H17
Assessment of first-principles structure optimisations, their impact on the band structures, and relative stability of polytypes in GaSe and InSe semiconductors — •Andrei Postnikov1, Juliana Srour1,2, Michael Badawi1, and Fouad El Haj Hassan2 — 1Université de Lorraine, LCP-A2MC, Metz, France — 2Université Libanaise, Faculté des Sciences, Beirut, Lebanon
Lattice parameters of β, γ, δ and ε polytypes of III-VI semiconductors GaSe and InSe are optimised in a sequence of first-principles (within the density functional theory) calculations, done with WIEN2k [1] and VASP [2] codes in comparison, the both being applied with a number of exchange-correlation (XC) “flavours”. An underestimation of the van der Waals (vdW) gap between the Se-(cation)-(cation)-Se double layers is largely corrected by inclusion of the vdW interaction according to the (semiempirical) Grimme scheme. A critical analysis is done of different XC types in what regards their impact on the accuracy of the structure prediction and on the fine placement of the valence / conduction bands. The band structures are discussed with respect to their relation to those in chalcopyrite-type Cu(Ga,In)Se2 compounds [3] and in the hexagonal In2Se3. For both binary compounds studied, different polytypes are ordered according to their energetic preference.
1. The WIEN2k code, http://www.wien2k.at .
2. The VASP code, http://www.vasp.at .
3. J.Srour, M. Badawi, F. El Haj Hassan, and A. V. Postnikov, to be published in phys.stat.solidi (c).