Electrical Modulation of Superconducting Critical Temperature in Liquid-Gated Thin Niobium Films

TL;DR

This study shows that the superconducting critical temperature and critical current of thin niobium films can be reversibly modulated using a liquid-gated device, enabling potential electrically-controlled superconducting switches.

Contribution

It introduces a liquid-gated approach to electrically modulate superconductivity in niobium films, demonstrating reversible control of Tc and critical current.

Findings

Tc can be modulated by about 0.1 K with gate voltage.

Superconducting critical current is tunable via gate voltage.

Reversible control suggests potential for superconducting switching devices.

Abstract

We demonstrate that the superconducting critical temperature (Tc) of thin niobium films can be electrically modulated in a liquid-gated geometry device. Tc can be suppressed and enhanced by applying positive and negative gate voltage, respectively, in a reversible manner within a range of about 0.1 K. At a fixed temperature below Tc, we observed that the superconducting critical current can be modulated by gate voltage. This result suggests a possibility of an electrically-controlled switching device operating at or above liquid helium temperature, where superconductivity can be turned on or off solely by the applied gate voltage.