Superconducting MoSi nanowires

TL;DR

This paper reports the fabrication of disordered superconducting MoSi nanowires with tunable properties, enabling the study of quantum phase slips and potential applications in quantum devices.

Contribution

It introduces a fabrication method for MoSi nanowires with controllable resistivity and diameter, facilitating exploration of quantum fluctuation effects in superconductivity.

Findings

Observation of crossover from conventional to fluctuation-affected superconductivity.

Detection of residual resistance and negative magnetoresistance at low temperatures.

Nanowire diameters enable study of quantum phase slips.

Abstract

We have fabricated disordered superconducting nanowires of molybdenium silicide. A molybdenium nanowire is first deposited on top of silicon, and the alloy is formed by rapid thermal annealing. The method allows tuning of the crystal growth to optimise, e.g., the resistivity of the alloy for potential applications in quantum phase slip devices and superconducting nanowire single-photon detectors. The wires have effective diameters from 42 to 79 nm, enabling the observation of crossover from conventional superconductivity to regimes affected by thermal and quantum fluctuations. In the smallest diameter wire and at temperatures well below the superconducting critical temperature, we observe residual resistance and negative magnetoresistance, which can be considered as fingerprints of quantum phase slips.