Universal critical exponent in class D superconductors

TL;DR

This study investigates the critical behavior of disordered class D superconductors, revealing universal critical exponents across different phase transitions and energy independence of critical disorder.

Contribution

It demonstrates that critical exponents are universal for insulator-insulator and insulator-metal transitions in class D superconductors and shows energy independence of critical disorder.

Findings

Critical exponents are identical for different transitions.

Critical disorder is energy independent.

Universal behavior in class D superconductor phase transitions.

Abstract

We study a physical system consisting of non-interacting quasiparticles in disordered superconductors that have neither time-reversal nor spin-rotation invariance. This system belongs to class D within the recent classification scheme of random matrix ensembles (RME) and its phase diagram contains three different phases: metallic and two distinct localized phases with different quantized thermal Hall conductances. We find that critical exponents describing different transitions (insulator-to-insulator and insulator-to-metal) are identical within the error of numerical calculations and also find that critical disorder of the insulator-to-metal transition is energy independent.