Signatures of topology in ballistic bulk transport of HgTe quantum wells

TL;DR

This paper investigates how bulk transport measurements in HgTe quantum wells can reveal topological order, showing that conductance and shot noise differ between trivial and non-trivial regimes, providing an alternative to edge-based detection.

Contribution

It demonstrates that bulk transport properties can serve as signatures of topological phases in HgTe quantum wells, expanding the methods for identifying topological order.

Findings

Conductance and shot noise differ between trivial and topological regimes.

Bulk properties can dominate edge contributions under certain conditions.

Bulk measurements can verify topological order independently of edge states.

Abstract

We calculate bulk transport properties of two-dimensional topological insulators based on HgTe quantum wells in the ballistic regime. Interestingly, we find that the conductance and the shot noise are distinctively different for the so-called normal regime (the topologically trivial case) and the so-called inverted regime (the topologically non-trivial case). Thus, it is possible to verify the topological order of a two-dimensional topological insulator not only via observable edge properties but also via observable bulk properties. This is important because we show that under certain conditions the bulk contribution can dominate the edge contribution which makes it essential to fully understand the former for the interpretation of future experiments in clean samples.