Effects of fabrication routes and material parameters on the control of superconducting currents by gate voltage

Authors: L. Ruf, T. Elalaily, C. Puglia, Yu. P. Ivanov, F. Joint, M. Berke, A. Iorio, P. Makk, G. De Simoni, S. Gasparinetti, G. Divitini, S. Csonka, F. Giazotto, E. Scheer, A. Di Bernardo

APL Mater. 11, 091113 (2023)

Abstract: The control of a superconducting current via the application of a gate voltage has been recently demonstrated in a variety of superconducting devices. Although the mechanism underlying this gate-controlled supercurrent (GCS) effect remains under debate, the GCS effect has raised great interest for the development of the superconducting equivalent of conventional metal-oxide semiconductor electronics. To date, however, the GCS effect has been mostly observed in superconducting devices made by additive patterning. Here, we show that devices made by subtractive patterning show a systematic absence of the GCS effect. Doing a microstructural analysis of these devices and comparing them to devices made by additive patterning, where we observe a GCS, we identify some material and physical parameters that are crucial for the observation of a GCS. We also show that some of the mechanisms proposed to explain the origin of the GCS effect are not universally relevant.

DOI: https://doi.org/10.1063/5.0159750