First-principles studies of surfaces of a metallic oxide : ReO3

Abstract

Transition metal oxides exhibit a wide range of behavior ranging from metallic conductivity, insulating, superconducting, ferroelectricity, colossal magnetoresistance, etc. They have applications ranging from catalysis, solar cells to electronic devices. Recently, a lot of interesting phenomena have been discovered at the interfaces of oxide heterostructures. Electron gas at the interface of two insulators [2], coexistence of superconductivity and magnetism [3], improper ferroelectricity at the interface of ferroelectric and paraelectric superlattice [4], etc. Also, the surfaces of TMO have been well studied both experimentally and theoretically [5]. The presence of a surface leads to breaking of translational symmetry. Atoms at the surface adjust to the breaking of symmetry by surface reconstruction, surface rumpling, and local polyhedral rearrangement. All these processes at the surface, the presence of dangling bonds and, low coordination number of atoms at the surface lead to new properties of a surface which may not be present in the bulk form. For example, at the surface of superconducting Sr2RuO4, the lattice distortion involving octahedral rotations couples with spin fluctuations leading to stable ferromagnetic state at the surface [6].