Criticality of the metal-topological insulator transition driven by disorder

TL;DR

This paper investigates the critical behavior of metal-topological insulator transitions driven by disorder, finding a universal critical exponent and exploring the topological phase diagram including the topological Anderson insulator phase.

Contribution

It provides the first estimation of the critical exponent for the metal-TAI transition and analyzes the symmetry-dependent Rashba spin-orbit coupling.

Findings

Critical exponent nu~2.7 for metal-TI transition

Critical exponent for metal-TAI transition is similar within error

Explicit form of Rashba spin-orbit coupling derived for C4v symmetry

Abstract

Employing scaling analysis of the localization length, we deduce the critical exponent of the metal-topological insulator (TI) transitions induced by disorder. The obtained exponent nu~2.7 shows no conspicuous deviation from the value established for metal-ordinary insulator transitions in systems of the symplectic class. We investigate the topological phase diagram upon carrier doping to reveal the nature of the so-called topological Anderson insulator (TAI) region. The critical exponent of the metal-TAI transition is also first estimated, shown to be undistinguishable from the above value within the numerical error. By symmetry considerations we determine the explicit form of Rashba spin-orbit coupling in systems of C4v point group symmetry.