Light induced non-volatile switching of superconductivity in single layer FeSe/SrTiO₃ heterostructures

The capability of using light to control the superconducting state is highly desirable for active quantum device applications. Since superconducting materials rarely exhibit strong photoresponses, and vice versa, optically sensitive materials are often not superconducting, the efficient coupling of these two characters in a single material can be a challenging task. Here we show that, in FeSe/SrTiO₃ heterostructures, the superconducting transition temperature in FeSe monolayer can be effectively raised by the interband photoexcitations in the SrTiO₃ substrate, attributed to a light induced metastable polar distortion uniquely enabled by the FeSe/SrTiO₃ interface, this effect only requires a less than 50 µW/cm² continuous-wave light field. The fast optical generation of superconducting zero resistance state is non-volatile but can be rapidly reversed by applying voltage pulses to the back of SrTiO₃ substrate. The capability of switching FeSe repeatedly and reliably between normal and superconducting states demonstrate the great potential of making energy-efficient quantum optoelectronics at designed correlated interfaces.