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HL: Fachverband Halbleiterphysik

HL 80: II-VI-compounds other than ZnO

HL 80.2: Vortrag

Donnerstag, 14. März 2013, 12:00–12:15, H15

Importance of oxygen vacancies for the two dimensional metallic state at the surface of SrTiO₃ — •Juan Shen, Harald O Jeschke, and Roser Valenti — Institut für Theoretische Physik, Goethe-Universität Frankfurt, Max-von-Laue-Straße 1, 60438 Frankfurt am Main

We analyze by means of density functional theory (DFT) the electronic structure of various oxygen-deficient (SrTiO₃) surface slabs. We find a significant surface reconstruction after introducing oxygen vacancies and we show that the charges resulting from surface-localized oxygen vacancies -independently of the oxygen concentration- redistribute in the surface region and deplete rapidly within a few layers from the surface suggesting the formation of a two-dimensional electron system (2DES). We also investigate possible oxygen-vacancy clustering effects and discuss our results in the context of recent angle-resolved photoemission spectroscopy observations of a highly metallic 2DES at the (001) vacuum-cleaved surface of SrTiO₃.