Spontaneous flux in a d-wave superconductor with time-reversal-symmetry-broken pairing state at {110} boundaries

TL;DR

This paper investigates how a complex d+is pairing state at {110} boundaries in a superconductor induces spontaneous flux, providing a potential experimental signature for time-reversal symmetry breaking.

Contribution

It numerically demonstrates the formation of measurable spontaneous flux from defect lines in a BTRS d+is superconductor at {110} boundaries.

Findings

Spontaneous flux is generated by defect lines with {110} orientation.

The flux strength is measurable and significant.

The results offer a way to detect BTRS pairing states experimentally.

Abstract

The induction of an s-wave component in a d-wave superconductor is considered. Near the {110}-oriented edges of such a sample, the induced s-wave order parameter together with d-wave component forms a complex combination d+e^{i\phi} s, which breaks the time reversal symmetry (BTRS) of the pairing state. As a result, the spontaneous current is created. We numerically study the current distribution and the formation of the spontaneous flux induced by the current. We show that the spontaneous flux formed from a number of defect lines with {110} orientation has a measurable strength. This result may provide a unambiguous way to check the existence of BTRS pairing state at {110}-oriented boundaries.