Electric field-induced superconductivity modulation in W-C nanowires*

In recent years, the electric field-induced control of superconductivity has been observed mostly in metallic superconducting materials [1]. However, so far the occurrence of this phenomenon is not fully understood in the framework of the microscopic BCS theory and it is still under debate. Here, we present a study of the electric field-induced modulation of superconductivity in W-C nanowires fabricated using focused ion beam induced deposition [2], a single step nanolithography method. It is experimentally found by electrical transport characterization that an increasing side-gate voltage applied in the vicinity of a 45 nm-wide W-C nanowire progressively decreases its superconducting critical current, up to a full suppression of the superconducting state. A theoretical model based on the GL theory explains this modulation by the squeezing of the superconducting state by the electric field. Given their broadened working temperature range and the smaller gate voltages required to modulate superconductivity compared to other materials, W-C nanostructures are promising candidates to serve as components in future superconducting devices with electric field-induced modulation.

[1] Paolucci, F. et al., AVS Quantum Sci. 1, 016501 (2019).

[2] Orús, P. et al., Sci. Rep. 11:17698 (2021).