Thermal metal-insulator transition in a helical topological superconductor

TL;DR

This paper investigates the topological phase transition in a 2D time-reversal symmetric superconductor, revealing a thermal metal-insulator transition with a critical localization length divergence.

Contribution

It demonstrates that the topological phase transition in a class-DIII network model corresponds to a thermal metal-insulator transition, with a critical exponent approximately twice that of chiral superconductors.

Findings

Localization length diverges at the transition with exponent ~2.0

Thermal conductance exhibits a metal-insulator transition

Critical behavior differs from chiral superconductor transitions

Abstract

Two-dimensional superconductors with time-reversal symmetry have a Z_2 topological invariant, that distinguishes phases with and without helical Majorana edge states. We study the topological phase transition in a class-DIII network model, and show that it is associated with a metal-insulator transition for the thermal conductance of the helical superconductor. The localization length diverges at the transition with critical exponent nu approx 2.0, about twice the known value in a chiral superconductor.