Electronic and structural properties of transition-metal/BaTiO3(001) interfaces are studied by first-principles local-density full-potential linearized augmented plane-wave calculations with slab models. Equilibrium interlayer separations between metal overlayers (for the 5d metals Ta, W, Ir, and Pt) and the BaTiO3 substrate are calculated by total-energy determinations. It is found that the preferred adsorption site for metal atoms on the BaTiO3 surface is above the O site and the metal-oxygen distance increases from Ta to Pt while the binding energy decreases. Significant hybridization is found between metal d states and the O 2p-Ti 3d states. The Fermi levels of the metals lie in the gap of BaTiO3 and metal-induced gap states, as suggested by Heine's theory [Proc. Phys. Soc. London 81, 300 (1962); Surf. Sci. 2, 1 (1964); Phys. Rev. 138, A1689 (1965)], are observed. The Schottky barrier in the interfaces is calculated by the position of EF in the gap and the dependence of the barrier height on the metal work function is different from either Schottky and Mott's or Bardeen's [Phys. Rev. 71, 717 (1947)] speculation.
|Number of pages||8|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - May 15 1997|
ASJC Scopus subject areas
- Condensed Matter Physics