Localized versus itinerant states created by multiple oxygen vacancies in SrTiO3

Harald Olaf Jeschke, Juan Shen, Roser Valentí

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

Oxygen vacancies in strontium titanate surfaces (SrTiO3) have been linked to the presence of a two-dimensional electron gas with unique behavior. We perform a detailed density functional theory study of the lattice and electronic structure of SrTiO3 slabs with multiple oxygen vacancies, with a main focus on two vacancies near a titanium dioxide terminated SrTiO3 surface. We conclude based on total energies that the two vacancies preferably inhabit the first two layers, i.e. they cluster vertically, while in the direction parallel to the surface, the vacancies show a weak tendency towards equal spacing. Analysis of the nonmagnetic electronic structure indicates that oxygen defects in the surface TiO2 layer lead to population of Ti states and thus itinerancy of the electrons donated by the oxygen vacancy. In contrast, electrons from subsurface oxygen vacancies populate Ti eg states and remain localized on the two Ti ions neighboring the vacancy. We find that both the formation of a bound oxygen-vacancy state composed of hybridized Ti 3eg and 4p states neighboring the oxygen vacancy as well as the elastic deformation after extracting oxygen contribute to the stabilization of the in-gap state.

Original languageEnglish
Article number023034
JournalNew Journal of Physics
Volume17
DOIs
Publication statusPublished - Feb 10 2015
Externally publishedYes

Fingerprint

oxygen
electronic structure
elastic deformation
titanium oxides
strontium
electron gas
surface layers
tendencies
slabs
electrons
stabilization
spacing
density functional theory
defects
ions
energy

Keywords

  • density functional theory
  • electronic structure
  • oxygen vacancies
  • perovskite oxides

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Localized versus itinerant states created by multiple oxygen vacancies in SrTiO3. / Jeschke, Harald Olaf; Shen, Juan; Valentí, Roser.

In: New Journal of Physics, Vol. 17, 023034, 10.02.2015.

Research output: Contribution to journalArticle

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