Ab initio study of the two-dimensional metallic state at the surface of SrTiO 3: Importance of oxygen vacancies

Juan Shen, Hunpyo Lee, Roser Valentí, Harald Olaf Jeschke

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46 Citations (Scopus)

Abstract

Motivated by recent angle-resolved photoemission spectroscopy observations of a highly metallic two-dimensional electron gas (2DEG) at the (001) vacuum-cleaved surface of SrTiO 3 and the subsequent discussion on the possible role of oxygen vacancies for the appearance of such a state, we analyze by means of density functional theory the electronic structure of various oxygen-deficient SrTiO 3 surface slabs. We find a significant surface reconstruction after introducing oxygen vacancies and we show that the charges resulting from surface-localized oxygen vacancies-independent of the oxygen concentration-redistribute in the surface region and deplete rapidly within a few layers from the surface suggesting the formation of a 2DEG. We discuss the underlying model emerging from such observations.

Original languageEnglish
Article number195119
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume86
Issue number19
DOIs
Publication statusPublished - Nov 15 2012
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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