Phase transformation-induced superconducting aluminium-silicon alloy rings

• Main Authors: Johnson, B. C, Stuiber, M, Creedon, D. L, Berhane, A, van Beveren, L. H. Willems, Rubanov, S, Cole, J. H, Mourik, V, Hamilton, A. R, Duty, T. L, McCallum, J. C
• Format: Journal Article
• Language: English
• Published: 12.07.2022
• Subjects: Physics - Materials Science; Physics - Mesoscale and Nanoscale Physics; Physics - Superconductivity
• DOI: 10.48550/arxiv.2207.05343

The development of a materials platform that exhibits both superconducting and semiconducting properties is an important endeavour for a range of emerging quantum technologies. We investigate the formation of superconductivity in nanowires fabricated with silicon-on-insulator (SOI). Aluminium from deposited contact electrodes is found to interdiffuses with the Si nanowire structures to form an Al-Si alloy along the entire length of the predefined nanowire device over micron length scales at temperatures well below that of the Al-Si eutectic. The resultant transformed nanowire structures are layered in geometry with a continuous Al-Si alloy wire sitting on the buried oxide of the SOI and a residual Si cap sitting on top of the wire. The phase transformed material is conformal with any predefined device patterns and the resultant structures are exceptionally smooth-walled compared to similar nanowire devices formed by silicidation processes. The superconducting properties of a mesoscopic AlSi ring formed on a SOI platform are investigated. Low temperature magnetoresistance oscillations, quantized in units of the fluxoid, h/2e, are observed.