Non-Quantized Edge Channel Conductance and Zero Conductance Fluctuation in Non-Hermitian Chern Insulators

TL;DR

This paper explores how non-Hermitian effects alter electron transport in Chern insulators, revealing non-quantized conductance with zero fluctuation and robustness against disorder, expanding understanding of topological edge states.

Contribution

It introduces a theoretical framework for non-Hermitian Chern insulators, showing distinct conductance behaviors and fluctuations based on non-Hermicity balance, and explains their physical origins.

Findings

Non-quantized conductance with zero fluctuation occurs under unbalanced non-Hermicity.

Quantized conductance with zero fluctuation persists under balanced non-Hermicity.

Both conductance regimes are robust against disorder.

Abstract

The quantized conductance plateaus and zero conductance fluctuation are the general consequence of electron transport in chiral edge states of Hermitian Chern insulators. Here we show that the physics of electron transport through chiral or helical edge channels becomes much richer when the non-Hermicity is allowed. In the presence of an unbalanced non-Hermicity where the chiral edge states have finite-lifetime, the conductance of the edge channels is not quantized, but its conductance fluctuation is zero. For the balanced non-Hermicity, however, the chiral edge states have infinite-lifetime, and the conductance is quantized as in the case of Hermitian Chern insulators. Both non-quantized and quantized conductance plateaus of zero conductance fluctuation are robust against disorders. We present a theory that explains the origin of the non-quantized conductance plateaus. The physics revealed here should also be true for the chiral and helical surface states in other topological materials such as quantum anomalous Hall systems, Weyl semimetals, and topological superconductors.