Surface structure of SrTiO{sub 3}(001)

Journal Article · Thu Nov 15 04:00:00 EST 2007 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PHYSREVB.76.195435· OSTI ID:21052783

Herger, R; Willmott, P R; Bunk, O; Schlepuetz, C M; Patterson, B D; Delley, B; Shneerson, V L; Lyman, P F; Saldin, D K ^[1]

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1. Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen (Switzerland)

We report on the structural determination of the surface of TiO{sub 2}-terminated SrTiO{sub 3}(001) using surface x-ray diffraction. The detailed analysis of two surface diffraction data sets are presented, one (cold) taken at room temperature in vacuum, and the other (hot) under typical conditions used for thin film growth. 49 different combinations of possible surface terminations are described for the cold structure, from which the final structure was chosen, consisting of a weighted mixture of a (1x1) relaxation and (2x1) and (2x2) reconstructions, simultaneously present at the surface. The structures are best modeled by a TiO{sub 2}-rich surface similar to that proposed by Erdman et al. [Nature (London) 419, 55 (2002)]. The reconstructions are energetically favorable according to density functional theory. They disappear within several minutes upon heating to the hot conditions, forming a termination very similar to the cold (1x1), but more puckered and higher in energy. Six additional models, suggested by direct methods and the literature, to describe the hot surface are also discussed. Direct methods confirm the TiO{sub 2}-rich termination and the atomic positions of the hot surface. The atomic coordinates for the two TiO{sub 2}-rich surfaces exhibit significant displacements down to three unit cells, which may have important implications on possible surface ferroelectric phenomena in SrTiO{sub 3}. Surface energy considerations suggest a temperature-induced order-disorder transition, produced by a mixing of the (2x1) and (2x2) reconstructions, to form the hot pseudo (1x1) structure. Electrostatic stability arguments provide circumstantial support for the experimentally determined TiO{sub 2}-rich surfaces.

• OSTI ID: 21052783
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Journal Name: Physical Review. B, Condensed Matter and Materials Physics Journal Issue: 19 Vol. 76; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
DENSITY FUNCTIONAL METHOD
FERROELECTRIC MATERIALS
HEATING
MIXTURES
ORDER-DISORDER TRANSFORMATIONS
STRONTIUM TITANATES
SURFACE ENERGY
SURFACES
TEMPERATURE RANGE 0273-0400 K
THIN FILMS
TITANIUM OXIDES
X-RAY DIFFRACTION