Electrically Tunable Optical Switching of a Mott Insulator- Band Insulator Interface

摘要

We report on the optical switching behavior of ultrathin LaTiO_3 (LTO) films epitaxially grown on (100) and (110) SrTiO_3 (STO). The metallic state of this heterostructure formed by deposition of an otherwise Mott insulator can be switched by an electric field applied in a field-effect transistor (FET) configuration or upon exposure to near-ultraviolet light. The photon-flux-induced switching can be enhanced or nullified by changing the polarity of the gate voltage. We present a scenario where electrons from the lower Hubbard band of LTO and oxygen defect states of STO accumulate at the interface. The extent of this accumulation is modified by electric and photon fields, giving rise to a potentially new electronic device.