First-principles calculations have been performed to study the interface electronic structure of $\text{Pt}/{\text{TiO}}_2$ and to analyze the rectifying property of the $\text{Pt}/{\text{TiO}}_2/\text{Pt}$ structure. For the stoichiometric interface, the metal-induced gap states (MIGS) have amplitude appreciably only at the interface ${\text{TiO}}_2$. We will show that the presence of MIGS makes oxygen-vacancy formation energy small at the interface. It is therefore expected that the interfacial ${\text{TiO}}_2$ layer can be easily reduced. We will then demonstrate that the Schottky barrier height is strongly affected by oxygen deficiency. According to the present calculation, the interface is of Schottky-contact type for the fully oxidized interfacial ${\text{TiO}}_2$ while it becomes almost ohmic for strongly reduced one.

• Received 5 June 2009

DOI:https://doi.org/10.1103/PhysRevB.80.195302