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

TL;DR

This study demonstrates a non-volatile, local control of superconductivity at LaAlO3/KTaO3(111) interfaces using a biased AFM tip, enabling rewritable electronic states with potential for advanced oxide electronics.

Contribution

It introduces a novel method for non-volatile, local tuning of interface conductivity and superconductivity via surface charge writing with an AFM tip.

Findings

Surface charge writing modulates interface conduction by over 8×10^13/cm^2.

The tuning effect remains stable for more than 20 hours at room temperature.

Rewritable superconducting, normal, and insulating states are achievable in the same heterostructure.

Abstract

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.