Quantitative analysis of quantum phase slips in superconducting MoGe nanowires revealed by switching-current statistics

TL;DR

This study quantitatively analyzes quantum and thermal phase slips in superconducting MoGe nanowires through switching-current statistics, providing evidence for quantum phase slips and exploring their dependence on wire properties.

Contribution

It introduces a method to measure quantum phase slips in homogeneous nanowires and investigates how wire resistance, morphology, and critical temperature affect phase-slip behavior.

Findings

Quantum phase slips are confirmed in homogeneous nanowires.

The crossover temperature Tq scales linearly with Tc.

In situ phase transformation enables direct study of wire properties.

Abstract

We measure quantum and thermal phase-slip rates using the standard deviation of the switching current in superconducting nanowires at high bias current. Our rigorous quantitative analysis provides firm evidence for the presence of quantum phase slips (QPS) in homogeneous nanowires. We observe that as temperature is lowered, thermal fluctuations freeze at a characteristic crossover temperature Tq, below which the dispersion of the switching current saturates to a constant value, indicating the presence of QPS. The scaling of the crossover temperature Tq with the critical temperature Tc is linear, which is consistent with the theory of macroscopic quantum tunneling. We can convert the wires from the initial amorphous phase to a single crystal phase, in situ, by applying calibrated voltage pulses. This technique allows us to probe directly the effects of the wire resistance, critical temperature and morphology on thermal and quantum phase slips.