Nanoscale control of LaAlO3/SrTiO3 metal-insulator transition using ultra-low-voltage electron-beam lithography

TL;DR

This paper introduces a rapid, non-destructive ultra-low-voltage electron-beam lithography method to precisely control the insulator-metal transition at LaAlO3/SrTiO3 interfaces, enabling high-resolution, reversible, and superconducting device fabrication.

Contribution

It presents a novel ULV-EBL technique that surpasses c-AFM in speed and resolution, expanding capabilities for nanoscale electronic device engineering.

Findings

Achieved ~10 nm resolution at 10 mm/s write speed

Demonstrated reversible conductivity changes via air exposure

Observed superconductivity in devices at milli-Kelvin temperatures

Abstract

We describe a method to control the insulator-metal transition at the LaAlO3/SrTiO3 interface using ultra-low-voltage electron beam lithography (ULV-EBL). Compared with previous reports that utilize conductive atomic-force-microscope lithography (c-AFM), this approach can provide comparable resolution (~10 nm) at write speeds (10 mm/s) that are up to 10,000x faster than c-AFM. The writing technique is non-destructive and the conductive state is reversible via prolonged exposure to air. Transport properties of representative devices are measured at milli-Kelvin temperatures, where superconducting behavior is observed. We also demonstrate the ability to create conducting devices on graphene/LaAlO3/SrTiO3 heterostructures. The underlying mechanism is believed to be closely related to the same mechanism regulating c-AFM-based methods.