Ballistic geometric resistance resonances in a single surface of a topological insulator

TL;DR

This paper reports the first observation of ballistic effects in a three-dimensional topological insulator by imposing a submicron periodic potential on a high-mobility HgTe surface, revealing geometric resistance resonances.

Contribution

It demonstrates ballistic motion and geometric resistance resonances in a 3D topological insulator, enabling potential nanometer-scale manipulation of Dirac electrons.

Findings

Observation of geometric resistance resonances

Ballistic transport in a 3D topological insulator

Manipulation of Dirac electrons at nanometer scale

Abstract

Transport in topological matter has shown a variety of novel phenomena over the last decade. Although numerous transport studies have been conducted on three-dimensional topological insulators (3D-TIs), study of ballistic motion and thus exploration of potential landscapes on a hundred nanometer scale is for the prevalent TI materials almost impossible due to their low carrier mobility. Therefore it is unknown whether helical Dirac electrons in TIs, bound to interfaces between topologically distinct materials, can be manipulated on the nanometer scale by local gates or locally etched regions. Here we impose a submicron periodic potential onto a single surface of Dirac electrons in high mobility strained mercury telluride (HgTe), which is a strong TI. Pronounced geometric resistance resonances constitute the first observation of a ballistic effect in 3D-TIs.