Key points are not available for this paper at this time.
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 (11) relaxation and (21) and (22) 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). . Both reconstructions have been shown by density functional theory to be energetically favorable. The calculated (11) 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.
Herger et al. (Thu,) studied this question.