Tunable anisotropic nonlinearity in superconductors with asymmetric antidot array

TL;DR

This paper investigates how spatial asymmetry in pinning potentials affects the nonlinear voltage response in superconductors, revealing the emergence of even Fourier components and directional dependence of nonlinearity near the phase transition.

Contribution

It demonstrates that asymmetry in pinning potentials induces anisotropic nonlinearity and even Fourier components in the voltage response of superconductors, enabling directional control of nonlinearity.

Findings

Asymmetry causes even Fourier components in voltage.

Nonlinearity depends on current direction.

Asymmetry enables low-resistive, directional nonlinearity.

Abstract

The influence of the spatial asymmetry of the pinning potential on the spectral composition of the voltage, induced in perforated superconducting Al bridges by the injection of a sinusoidal bias current, was investigated. The loss of the mirror symmetry of the pinning potential leads to the appearance of even Fourier components in the induced voltage in the vicinity of the superconducting phase transition line on the H-T diagram (H is the external magnetic field, T is temperature). Artificially-introduced asymmetry for vortex motion makes it possible to create low-resistive materials, in which nonlinearity depends on the direction of injected electrical currents.