Scale-Invariant Dissipationless Chiral Transport in Magnetic Topological Insulators beyond the Two-Dimensional Limit

TL;DR

This study demonstrates that the quantum anomalous Hall effect and chiral transport persist in thick magnetic topological insulator films beyond the 2D limit, showing potential for scalable low-power electronic applications.

Contribution

It reveals the persistence of QAHE and chiral edge conduction in millimeter-sized films beyond the 2D hybridization limit, expanding understanding of topological phases.

Findings

Quantized Hall conductance persists in thick films.

Chiral edge conduction confirmed by non-local measurements.

Scale-invariant dissipationless transport observed on macroscopic scales.

Abstract

We investigate the quantum anomalous Hall Effect (QAHE) and related chiral transport in the millimeter-size (Cr0.12Bi0.26Sb0.62)2Te3 films. With high sample quality and robust magnetism at low temperatures, the quantized Hall conductance of e2/h is found to persist even when the film thickness is beyond the two-dimensional (2D) hybridization limit. Meanwhile, the Chern insulator-featured chiral edge conduction is manifested by the non-local transport measurements. In contrast to the 2D hybridized thin film, an additional weakly field-dependent longitudinal resistance is observed in the 10 quintuple-layer film, suggesting the influence of the film thickness on the dissipative edge channel in the QAHE regime. The extension of QAHE into the three-dimensional thickness region addresses the universality of this quantum transport phenomenon and motivates the exploration of new QAHE phases with tunable Chern numbers. In addition, the observation of the scale-invariant dissipationless chiral propagation on a macroscopic scale makes a major stride towards ideal low-power interconnect applications.