Annealing temperature dependence on the electronic structure of the reduced SrTiO 3 (111) surface

Abstract

The electronic structure of the reduced SrTiO 3 (111) surface prepared by annealing in ultrahigh vacuum has been studied using photoemission spectroscopy. In the photoemission spectrum of the reduced surface after annealing at 800°C, a metallic state with a sharp Fermi cut-off is observed in the band gap region. For the reduced surface prepared by annealing at 1200°C, on the other hand, the metallic state becomes drastically weak and a localized state centered at ∼1.1 eV below the Fermi level is observed in the band gap region. Based on the low energy electron diffraction results, we will discuss the relationship between the spectral feature of these band gap states and the surface geometric structure.