title: Surface of strontium titanate.
abstract: We report the first complete determination, using surface x-ray diffraction, of the surface structure of TiO2-terminated SrTiO3(001), both at room temperature in vacuum, and also hot, under typical conditions used for thin film growth. The cold structure consists of a mixture of a (1x1) relaxation and (2x1) and (2x2) reconstructions. The latter disappear over several minutes upon heating. The structures are best modeled by a TiO2-rich surface similar to that proposed by Erdman et al. [Nature (London) 419, 55 (2002).10.1038/nature01010]. Both reconstructions have been shown by density functional theory to be energetically favorable. The calculated (1x1) surface energy is higher, indicating that it may be a disordered mixture of the reconstructions. Atomic displacements are significant down to three unit cells, which may have important implications on possible surface ferroelectric phenomena in SrTiO3.
authors.affiliation: Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen, Switzerland.
authors.forename: R
authors.initials: R
authors.lastname: Herger
authors.forename: P R
authors.initials: PR
authors.lastname: Willmott
authors.forename: O
authors.initials: O
authors.lastname: Bunk
authors.forename: C M
authors.initials: CM
authors.lastname: Schlepütz
authors.forename: B D
authors.initials: BD
authors.lastname: Patterson
authors.forename: B
authors.initials: B
authors.lastname: Delley