Evidence for charge-vortex duality at the LaAlO$_3$/SrTiO$_3$ interface

TL;DR

This paper provides experimental evidence for charge-vortex duality at the LaAlO3/SrTiO3 interface, demonstrating how vortex motion influences electronic transport across the superconductor-insulator transition.

Contribution

It reports a novel experimental manifestation of charge-vortex duality driven by ferromagnetic vortex dynamics at the LAO/STO interface.

Findings

Vortex motion affects resistance and conductance depending on the transition side.

Experimental evidence supports charge-vortex duality at oxide interfaces.

Magnetization dynamics induce observable transport changes.

Abstract

The concept of duality has proved extremely powerful in extending our understanding in many areas of physics (1, 2). Charge-vortex duality has been proposed (3, 4) as a model to understand the superconductor to insulator transition (SIT) in disordered thin films (5, 6) and Josephson junction arrays (7, 8, 9). In this model, on the superconducting side, one has delocalized Cooper pairs but localized vortices; while on the insulating side, one has localized Cooper pairs but mobile vortices. Here we show a new experimental manifestation of this duality in the electron gas that forms at the interface between LaAlO$_3$ (LAO) and SrTiO$_3$ (STO) (10, 11, 12, 13, 14). The effect is due to the motion of vortices generated by the magnetization dynamics of the ferromagnet that also forms at the same interface (14, 15, 16), which results in an increase in resistance on the superconducting side of the transition, but an increase in conductance on the insulating side.