Disorder induced superconducting ratchet effect in nanowires

TL;DR

This study reports a superconducting ratchet effect in disordered nanowires, where an asymmetric voltage develops under ac bias, influenced by disorder, temperature, and magnetic field, revealing vortex dynamics near the superconductor-insulator transition.

Contribution

It demonstrates the disorder-induced superconducting ratchet effect in nanowires, highlighting the role of inhomogeneity and vortex motion in disordered superconductors.

Findings

Voltage exhibits quasi-periodic magneto-oscillations.

Voltage magnitude increases below T_C and saturates at low T.

Suppression of voltage with decreased disorder.

Abstract

A dc voltage drop develops along amorphous indium oxide nanowires that are exposed to an ac bias source. This voltage is anti-symmetric with magnetic field and is characterized by sample specific quasi-periodic magneto-voltage oscillations. The voltage magnitude increases with decreasing temperature below $T_{C}$ but saturates at low T. As the disorder of the sample is decreased, the dc voltage is suppressed. We suggest that this rectification is a manifestation of the superconducting ratchet effect in which disorder and geometrical confinement play the role of asymmetric pinning centers. This effect demonstrates the importance of inherent inhomogeneity and vortex motion in the superconductor-insulator transition of disordered superconductors.