Surface charge writing and non-volatile control of superconductivity in LaAlO3/KTaO3(111) heterostructure

The oxide interface between LaAlO3 and KTaO3(111) can host an electron gas that condenses into superconductivity at low temperatures. In this work, we demonstrate a local and non-volatile control of this electron gas using a biased conducting atomic force microscope tip. By scanning the tip, charges can be accumulated on the surface of LaAlO3, which subsequently tune the conduction of the buried LaAlO3/KTaO3(111) interface largely, varying from conducting (superconducting) to insulating states. The tuning effects are stable for > 20 h at room temperature. The maximum modulation of carrier density is > 8 times 10^13/cm^2. This result suggests a new model system in which rewritable superconducting, normal, and insulating states can be flexibly defined in the same material on demand.