Some Experimental Signatures to look for Time-reversal Violating superconductors

TL;DR

This paper explores experimental signatures of topological structures in unconventional superconductors with time-reversal symmetry breaking, focusing on surface states and magnetic flux in specific superconductor models.

Contribution

It analyzes topological surface states and magnetic flux signatures in unconventional superconductors with complex order parameters, proposing new experimental approaches.

Findings

Surface states observable via Andreev tunneling on specific crystal surfaces.

Magnetic flux trapping in superconducting rings with grain-boundary Josephson junctions.

Review of previous experiments and suggestions for new experimental tests.

Abstract

We discuss some experimental signatures associated with the topological structures of unconventional superconductor order parameters of form $d_{x^2-y^2}+ix$, where $x=s,p_x \pm p_y$, or $d_{xy}$. Specifically, we study the topological surface states on the $(110)$ and equivalent surfaces of such superconductors which are observable in Andreev tunneling experiments, as well as evaluate the magnetic flux trapped in superconducting rings of such superconductors with multiple grain-boundary Josephson junctions. Previous experiments are examined and several new experiments suggested.