Spontaneous surface flux pattern in chiral p-wave superconductors - revisited

TL;DR

This study uses Ginzburg Landau theory to analyze spontaneous magnetic flux patterns at the edges of chiral p-wave superconductors, revealing their sensitivity to boundary conditions and challenging their universality.

Contribution

It provides a detailed numerical analysis of flux patterns in chiral p-wave superconductors considering various boundary conditions and electronic features, showing their non-universality.

Findings

Flux patterns are highly sensitive to boundary conditions.

Spontaneous magnetic flux is not a universal feature.

No direct experimental signs of such flux in Sr2RuO4.

Abstract

In chiral $p$-wave superconductors, magnetic flux patterns may appear spontaneously when translational symmetry is broken such as at surfaces, domain walls, or impurities. However, in the candidate material Sr$_2$RuO$_4$ no direct signs of such magnetic fields have been detected experimentally. In this paper, the flux pattern at the edge of a disk-shaped sample is examined using the phenomenological Ginzburg Landau approach. The detailed shape of the flux pattern, including self-screening, is computed numerically for different surface types by systematically scanning a range of boundary conditions. Moreover, specific features of the electronic structure are included qualitatively through the coefficients in the Ginzburg Landau functional. Both the shape and the magnitude of the flux pattern are found to be highly sensitive to all considered parameters. In conclusion, such spontaneous magnetic flux patterns are not a universal feature of chiral $p$-wave superconductors.