Metallic Interface between Two Insulating Phases of La_1-xSr_xCoO_3-

Metal-insulator transitions occurring in several transition metal oxides (TMOs) can be used to realize energy-efficient resistive switching devices, which in turn can be utilized as basic components of neuromorphic architectures. Using first-principles calculations, we predict the occurrence of an insulator-to-metal transition at the interface of two insulators, the perovskite (P) and brownmillerite (BM) phases of promising TMOs for neuromorphic applications, LaSrCoO3-delta. The electronic structure of the interface can be engineered by controlling strain, Sr content, and oxygen vacancy concentration. A metallic interface arises from the combined effect of structural distortions and charge transfer between the BM and P phases, which leads to interfacial orbital reconstruction. Our results point to the possibility of realizing energy-efficient resistive switching states at a two-dimensional interface within the same TMO solid, thus opening new routes for the design of low-power neuromorphic devices.