Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 19: Clean surfaces I
O 19.5: Vortrag
Montag, 26. März 2012, 18:30–18:45, A 053
Ab-initio study of tin dioxide surfaces: stability and electronic structure — •Sebastian Küfner1, Andre Schleife2,1, Benjamin Höffling1, and Friedhelm Bechstedt1 — 1Institut für Festkörpertheorie und -optik, Friedrich-Schiller-Universität, Max-Wien-Platz 1, D-07743 Jena, Germany — 2Department of Physics, University of California, Santa Barbara, California 93106-9530, USA
SnO2 as an transparent conducting oxide is an interesting material for application in transparent circuits, photovoltaic or optoelectronic devices. However, the electronic structures as well as the relative stability of different orientations and terminations of SnO2 surfaces are not well known.
We apply the density functional theory to calculate the total energies and the atomic geometries of the low-index surfaces (001), (100), (110), (111) of rutile SnO2. From a comparison to the quasiparticle bulk band structure we conclude that the results of the approximate LDA-1/2 scheme are sufficiently accurate while they can be obtained at significantly lower computational cost. Therefore, the LDA-1/2 method is used to calculate the surface band structures.
Calculating the surface free energy depending on the oxygen chemical potential, we find the oxygen-terminated (100) and (110) surfaces to be most stable, in accordance with experiments and other ab-initio results. We show that the insulating character is conserved for the surfaces (except for the tin terminated (110) one) even though surface states appear in the fundamental band gap. Furthermore, we obtain the ionization energies and electron affinities.