Local insulator-to-superconductor transition in amorphous InO$_x$ films modulated by e-beam irradiation

TL;DR

This paper introduces a novel electron-beam technique to locally induce and control superconductivity in amorphous InO$_x$ films, enabling precise post-fabrication modulation of electrical properties at the microscale.

Contribution

It demonstrates a new method for locally turning insulating films into superconductors with tunable transition temperatures using electron-beam irradiation.

Findings

Superconductivity can be induced in amorphous InO$_x$ films via e-beam exposure.

The transition temperature $T_c$ can be adjusted up to 2.8 K by varying electron dose and voltage.

The technique allows independent control of electrical properties in identical samples.

Abstract

We present a novel method enabling precise post-fabrication modulation of the electrical resistance in micrometer-scale regions of amorphous indium oxide (a-InO$_x$) films. By subjecting initially insulating films to an electron beam at room temperature, we demonstrate that the exposed region of the films becomes superconducting. The resultant superconducting transition temperature ($T_c$) is adjustable up to 2.8 K by changing the electron dose and accelerating voltage. This technique offers a compelling alternative to traditional a-InO$_x$ annealing methods for both fundamental investigations and practical applications. Moreover, it empowers independent adjustment of electrical properties across initially identical a-InO$_x$ samples on the same substrate, facilitating the creation of superconducting microstructures with precise $T_c$ control at the micrometer scale. Some possible mechanisms for the observed resistance modifications are discussed.