Strong Aharonov-Bohm quantum interference in simply-connected LaAlO$_3$/SrTiO$_3$ structures

TL;DR

This paper demonstrates Aharonov-Bohm quantum interference in simply-connected LaAlO3/SrTiO3 devices, revealing multi-periodic oscillations and magnetic hysteresis, with potential implications for quantum device engineering.

Contribution

It reports the first observation of AB interference in simply-connected oxide interfaces, highlighting inhomogeneous magnetic effects and contrasting behavior with multiply-connected structures.

Findings

AB oscillations approach e^2/h in amplitude

Multi-periodic and quasiperiodic interference patterns observed

Nanoscale ring devices lack AB signatures

Abstract

We report Aharonov-Bohm (AB)-type quantum interference in simply-connected devices created at the LaAlO$_3$/SrTiO$_3$ interface using conductive-atomic force microscope (c-AFM) lithography. The oscillations are multi-periodic functions of magnetic field strength, and they exhibit a substantial magnetic hysteresis with frequencies that depends on the magnetic sweep direction. The oscillation amplitude for the lowest two frequencies approaches $e^2/h$, consistent with the theoretical maximum for the AB effect, and harmonics up to third order are observable. Broadband quasiperiodic behavior is reported in a fraction of simply-connected electron waveguide devices that exhibit magnetic asymmetries. Curiously, nanoscale ring devices that are multiply-connected lack signatures of AB quantum interference. The interference phenomena are associated with an inhomogeneous magnetic landscape within the LaAlO$_3$/SrTiO$_3$ nanostructures.