Electronic structures of the SrTiO3(110) surface in different reconstructions.

The surface of SrTiO(3)(110) single crystal is prepared in monophase with different reconstructions. The increase of surface Ti concentration is responsible for the evolution of the reconstruction from (4×1) to (2×8), and to a new (1×10) structure. It also induces the enhancement of the surface metallicity, characterized by the appearance of the in-gap states and the increasing Drude weight as measured by the electron and photoelectron spectroscopies. We attribute the metallicity to the reduced Ti ions, which is consistent with the observed band structures and the shift of the phonon energy. It is indicated that a heterointerface between a reduced titanate layer and SrTiO(3) crystal with unique electronic structure can be obtained by the simple treatment.