KTaO3-Based Supercurrent Diode

TL;DR

This paper demonstrates a supercurrent diode effect in LAO/KTO devices by nanoscale patterning of superconducting weak links, showing controllable nonreciprocal critical currents influenced by device geometry and magnetic fields.

Contribution

It introduces a reconfigurable superconducting weak link platform at the LAO/KTO interface to realize and control the supercurrent diode effect.

Findings

SDE observed with up to 13% rectification efficiency.

Polarity of SDE can be reversed by changing weak link position.

SDE originates from asymmetric vortex motion due to device geometry.

Abstract

The supercurrent diode effect (SDE), characterized by nonreciprocal critical currents, represents a promising building block for future dissipationless electronics and quantum circuits. Realizing SDE requires breaking both time-reversal and inversion symmetry in the device. Here we use conductive atomic force microscopy (c-AFM) lithography to pattern reconfigurable superconducting weak links (WLs) at the LaAlO3/KTaO3 (LAO/KTO) interface. By deliberately engineering the WL geometry at the nanoscale, we realize SDE in these devices in the presence of modest out-of-plane magnetic fields. The SDE polarity can be reversed by simply changing the WL position, and the rectification efficiency reaches up to 13% under optimal magnetic field conditions. Time-dependent Ginzburg-Landau simulations reveal that the observed SDE originates from asymmetric vortex motion in the inversion-symmetry-breaking device geometry. This demonstration of SDE in the LAO/KTO system establishes a versatile platform for investigating and engineering vortex dynamics, forming the basis for engineered quantum circuit elements.