Dissipation in Quasi One-Dimensional Superconducting Single-Crystal Sn Nanowires

TL;DR

This study investigates dissipation mechanisms in single-crystal Sn nanowires, revealing size-dependent residual resistance and phase slip phenomena, with implications for understanding one-dimensional superconductivity.

Contribution

It provides new insights into the intrinsic dissipation processes and phase slip behavior in ultra-thin superconducting nanowires, extending existing models.

Findings

Residual resistance persists in nanowires below Tc.

Logarithmic resistance behavior suggests thermally activated and quantum phase slips.

Discrete voltage steps indicate complex phase slip dynamics.

Abstract

Electrical transport measurements were made on single-crystal Sn nanowires to understand the intrinsic dissipation mechanisms of a one-dimensional superconductor. While the resistance of wires of diameter larger than 70 nm drops precipitately to zero at Tc near 3.7 K, a residual resistive tail extending down to low temperature is found for wires with diameters of 20 and 40 nm. As a function of temperature, the logarithm of the residual resistance appears as two linear sections, one within a few tenths of a degree below Tc and the other extending down to at least 0.47 K, the minimum temperature of the measurements. The residual resistance is found to be ohmic at all temperatures below Tc of Sn. These findings are suggestive of a thermally activated phase slip process near Tc and quantum fluctuation-induced phase slip process in the low temperature regime. When the excitation current exceeds a critical value, the voltage-current (V-I) curves show a series of discrete steps in approaching the normal state. These steps cannot be fully understood with the classical Skocpol-Beasley-Tinkham phase slip center model (PSC), but can be qualitatively accounted for partly by the PSC model modified by Michotte et al.