Disordered semimetal with parity anomaly

Abstract

<p>The parity anomalous semimetal (PAS) phase is a topological state of matter exhibiting a semimetallic nature<br>and a half-quantized Hall conductance of e2/h (e is the elementary charge and h is the Planck constant).<br>In this work, we investigate the disorder-driven topological phase transition in a semimagnetic narrow-gap<br>band insulator thin film. We demonstrate that strong disorder induces a transition from the narrow-gap band<br>insulator to a PAS phase, accompanied by the emergence of a single gapless Dirac cone—the hallmark of the<br>half-quantized Hall effect. Calculations of the local density of states reveal the spectral evolution underlying<br>this transition, while finite-size scaling of the real-space Hall conductivity confirms the robustness of the<br>half-quantized plateau over a finite range of disorder strengths. Our findings reveal disorder as a potent tool for<br>engineering topological phases, in which the interplay between topology and localization in quantum materials<br>warrants further exploration.<br></p>