We investigate the quantum anomalous Hall effect (QAHE) and related chiral transport in the millimeter-size ${({\mathrm{Cr}}_{0.12}{\mathrm{Bi}}_{0.26}{\mathrm{Sb}}_{0.62})}_2{\mathrm{Te}}_3$ films. With high sample quality and robust magnetism at low temperatures, the quantized Hall conductance of $e^2/h$ 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 nonlocal transport measurements. In contrast to the 2D hybridized thin film, an additional weakly field-dependent longitudinal resistance is observed in the ten-quintuple-layer film, suggesting the influence of the film thickness on the dissipative edge channel in the QAHE regime. The extension of the 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 scale-invariant dissipationless chiral propagation on a macroscopic scale makes a major stride towards ideal low-power interconnect applications.

• Received 26 May 2014

DOI:https://doi.org/10.1103/PhysRevLett.113.137201