Regensburg 1998 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 36: Theorie
HL 36.4: Vortrag
Donnerstag, 26. März 1998, 17:15–17:30, H15
Electronic structure of II-VI compounds: ab initio GW calculations and UV photoemission experiments in comparison — •A. Fleszar1, W. Hanke1, M. Nagelstraßer2, H. Dröge2, and H.-P. Steinrück2 — 1Theoretische Physik I — 2Experimentelle Physik II, Universität Würzburg, Am Hubland, D-97074 Würzburg
The electronic structure of II-VI compounds (BeTe, BeSe, CdTe, ZnSe, MgTe, etc.) has been studied by means of the ab-initio GW approach. With the calculated quasiparticle energy bands, their lifetimes and the inelastic mean-free paths as an input, the theoretical photoemission (PE) energy-distribution curves (EDC) have been determined under the assumption of direct transitions between the bulk-Bloch states. The calculated EDC curves are compared with the PE measurements done at BESSY. It turns out that the use of first-principles final states in the calculation of the PE current results in a very good agreement with experiment and gives another - more plausible - interpretation of the origin of various measured peaks as would be obtained with the standard assumption of free-electron final states. The importance of various factors, such as the energy broadening of final states, which gives rise to their finite lifetimes and mean-free paths, or the proper account of the specific selection rules for the photoemission process, will be discussed.
This work was supported by the DFG via the SFB 410.