Interband interference effects at the edge of a multiband chiral p-wave superconductor

TL;DR

This paper investigates how interband interference in multiband chiral p-wave superconductors, like Sr$_2$RuO$_4$, affects edge states, currents, and tunneling conductance, revealing significant modifications due to phase differences between bands.

Contribution

It introduces a detailed analysis of interband interference effects on edge phenomena in multiband chiral superconductors, highlighting their impact on measurable edge properties.

Findings

Interband interference can significantly alter edge current distributions.

Edge conductance is affected by phase differences between bands.

Results are relevant for understanding Sr$_2$RuO$_4$ and similar multiband superconductors.

Abstract

Chiral superconductors support chiral edge modes and potentially spontaneous edge currents at their boundaries. Motivated by the putative multiband chiral p-wave superconductor Sr$_2$RuO$_4$, we study the influence of the interference between different bands at the edges, which may appear in the presence of moderate edge disorder or in edge tunneling measurements. We show that interband interference can strongly modify the measurable quantities at the edges when the order parameter exhibits phase difference between the bands. This is illustrated by investigating the edge dispersion and the edge current distribution in the presence of interband mixing, as well as the conductance at a tunneling junction. The results are discussed in connection with the putative chiral p-wave superconductor Sr$_2$RuO$_4$. In passing, we also discuss similar interference effects in multiband models with other pairing symmetries.