Spontaneous Edge Current in Higher Chirality Superconductors

TL;DR

This study investigates how temperature, surface roughness, and Meissner screening influence spontaneous edge currents in higher chirality superconductors, revealing temperature-dependent behavior and surface current inversion phenomena.

Contribution

It provides a detailed analysis of edge current behavior considering surface roughness and temperature effects, including the discovery of current inversion in chiral d-wave superconductors.

Findings

Spontaneous edge current peaks near half the transition temperature.

Surface roughness can induce a current inversion in chiral d-wave superconductors.

Current inversion is non-universal beyond the continuum limit, as shown by lattice calculations.

Abstract

The effects of finite temperature, Meissner screening and surface roughness on the spontaneous edge current for higher chirality quasi-two dimensional superconductors are studied in the continuum limit using the quasiclassical Eilenberger equations. We find that the total spontaneous current is non-zero at finite temperature $T$ and maximized near $T=T_c/2$, where $T_c$ is the transition temperature, although it vanishes at $T=0$. In the presence of surface roughness, we observe a surface current inversion in the chiral $d$-wave case that can be understood in terms of a disorder induced $s$-wave pairing component in the rough surface regime. This conclusion is supported by a Ginzburg-Landau analysis. However, this current inversion is non-universal beyond the continuum limit as demonstrated by self-consistent lattice Bogoliubov-de Gennes calculations.