In-plane electronic confinement in superconducting LaAlO$_3$/SrTiO$_3$ nanostructures

TL;DR

This paper demonstrates the fabrication and characterization of nanoscale superconducting devices based on the LaAlO$_3$/SrTiO$_3$ interface, showing that lateral confinement preserves transport properties and enables tunable superconductivity.

Contribution

It introduces a method to reliably confine the 2DEG at the LaAlO$_3$/SrTiO$_3$ interface at the nanoscale without altering its transport properties, paving the way for quantum electronic devices.

Findings

Devices exhibit superconductivity tunable by electric field.

Transport parameters remain unchanged after fabrication.

Universal conductance fluctuations indicate phase-coherent transport.

Abstract

We describe the transport properties of mesoscopic devices based on the two dimensional electron gas (2DEG) present at the LaAlO$_3$/SrTiO$_3$ interface. Bridges with lateral dimensions down to 500~nm were realized using electron beam lithography. Their detailed characterization shows that processing and confinement do not alter the transport parameters of the 2DEG. The devices exhibit superconducting behavior tunable by electric field effect. In the normal state, we measured universal conductance fluctuations, signature of phase-coherent transport in small structures. The achievement of reliable lateral confinement of the 2DEG opens the way to the realization of quantum electronic devices at the LaAlO$_3$/SrTiO$_3$ interface.