Electric field control of superconductivity at the LaAlO3/KTaO3(111) interface

The oxide interface between LaAlO3 and KTaO3(111) can harbor a superconducting state. We report that by applying a gate voltage (V-G) across KTaO3, the interface can be continuously tuned from superconducting into insulating states, yielding a dome-shaped T-c-V-G dependence, where T-c is the transition temperature. The electric gating has only a minor effect on carrier density but a strong one on mobility. We interpret the tuning of mobility in terms of change in the spatial profile of the carriers in the interface and hence, effective disorder. As the temperature is decreased, the resistance saturates at the lowest temperature on both superconducting and insulating sides, suggesting the emergence of a quantum metallic state associated with a failed superconductor and/or fragile insulator.

Automated summary

The study shows that the superconducting state at the oxide interface between LaAlO3 and KTaO3(111) can be tuned by applying a gate voltage across KTaO3, resulting in a dome-shaped dependence of transition temperature on gate voltage. The electric gating affects mobility more than carrier density. As the temperature decreases, the resistance saturates at the lowest temperature on both superconducting and insulating sides, indicating the emergence of a quantum metallic state associated with a failed superconductor and/or fragile insulator.