Anomalous Coherence Length of Majorana Zero Modes at Vortices in Superconducting Topological Insulators

TL;DR

This paper reveals that the coherence length of Majorana zero modes at vortices in superconducting topological insulators is independent of the superconducting order parameter and is determined by the material's intrinsic properties, highlighting a fundamental topological difference.

Contribution

It demonstrates an anomalous coherence length behavior of Majorana zero modes in topological insulator/superconductor heterostructures, contrasting with p-wave superconductors.

Findings

Coherence length is independent of superconducting order parameter.

Determined by intrinsic properties of the topological insulator.

Shows topological distinction from p-wave superconductors.

Abstract

The coherence length of two Majorana zero energy modes in a p-wave topological superconductor is inversely proportional to the superconducting order parameter. We studied the finite size effect of the Majorana zero modes at vortices in a topological insulator/superconductor heterostructure in the presence of a vortex and found that the the coherence length of the two zero energy modes at the terminals of a vortex line is independent of superconducting order parameter, and determined by the intrinsic properties of the topological insulator. This anomalous property illustrates that the superconducting topological insulator is topologically distinct, contrary to a $p$-wave topological superconductor.