Stability of oxygen vacancies at metal/oxide interfaces.

We investigated the influence of work function and charge doping on the formation of oxygen vacancies in metal/oxide heterojunctions by first-principles calculations. SrTiO is used as a typical oxide. Simple metals Pt, Au and Ag are used as electrodes. We show that electron doping could improve the formation energy of oxygen vacancies. In such a heterojunction, we found that the work function of the metal electrode affects the stability of oxygen vacancies in SrTiO. For an electrode with a smaller work function, more electrons are induced and accumulated in the oxides near the interface and improve the formation energy of oxygen vacancies. We also studied the effect of ferroelectric polarization in a heterojunction of metal/BaTiO and found similar properties. We hope that our work could help in the design of complex-oxide-based electronic devices.