Single-edge transport in InAs/GaSb quantum spin Hall insulator

François Couëdo, Hiroshi Irie, Kyoichi Suzuki, Koji Onomitsu, Koji Muraki

Published 2016-06-06Version 1

We report transport measurements in a single edge channel of an InAs/GaSb quantum spin Hall insulator, where the conduction occurs through only one pair of counter-propagating edge modes. By using a specific sample design involving highly asymmetric current paths, we electrically isolate a single edge channel of the two-dimensional topological insulator from the other edge. This enables us to probe a single edge by multi-terminal measurements. Both two-terminal and four-terminal resistances show a nearly quantized plateau around $h/e^2$ for a 4-$\mu$m-long edge, indicating quasi-ballistic transport. Our approach is advantageous in that it allows us to gain insight into a microscopic region from local measurements.