Magnetic Flux Periodicity in Second Order Topological Superconductors

TL;DR

This paper predicts that second-order topological superconductors exhibit a magnetic flux periodicity of hc/e due to Majorana corner modes, differing from conventional superconductors, and this periodicity reverts at the trivial transition.

Contribution

It theoretically demonstrates the flux periodicity change from hc/e to hc/2e in second-order topological superconductors linked to Majorana modes.

Findings

Flux periodicity is hc/e in second-order topological superconductors.

Periodicity reverts to hc/2e at the trivial phase transition.

Doubling of periodicity indicates non-trivial topology.

Abstract

The magnetic flux periodicity of $\frac{hc}{2e}$ is a well known manifestation of Cooper pairing in typical s-wave superconductors. In this paper we theoretically show that the flux periodicity of a two-dimensional second-order topological superconductor, which features zero-energy Majorana modes localized at the corners of the sample, is $\frac{hc}{e}$ instead. We further show that the periodicity changes back to $\frac{hc}{2e}$ at the transition to a topologically trivial superconductor, where the Majorana modes hybridize with the bulk states, demonstrating that the doubling of periodicity is a manifestation of the non-trivial topology of the state.