Sketched Nanoscale KTaO3-Based Superconducting Quantum Interference Device

The discovery of two-dimensional superconductivity in LAO/KTO (111) and (110) interfaces has raised significant interest in this system. Here we report creation of nanoscale direct current superconducting quantum interference device (DC-SQUID), created by conductive atomic force microscope (c-AFM) lithographic control of conductivity at the LAO/KTO(110) interface. The field modulation of its critical current, , is dominated by the large kinetic inductance of superconducting 2DEG in KTO. The critical current of the SQUID is tunable by electrical gating from the back, due to the large dielectric constant of KTO. The demonstration of SQUID effect in KTO opens up the possibilities for probing the underlying physics of KTO superconductivity, such as the role of spin-orbit-coupling, pairing symmetry, and inhomogeneity. It also further implies that KTO could serve as a foundation for future quantum devices.