Transport signatures of a Floquet topological transition at the helical edge

TL;DR

This paper predicts a Floquet topological phase transition in helical edge states of 2D topological insulators induced by a time-periodic electric field, which can be detected via conductance measurements.

Contribution

It introduces the concept of a dynamical topological quantum phase transition in Floquet systems with helical edges, linking it to observable conductance signatures.

Findings

Quantum point contact with helical edges can undergo a Floquet topological transition.

The transition can be detected through conductance measurements.

Theoretical prediction of Floquet topological phenomena in topological insulators.

Abstract

The manipulation of the helical edge states of two-dimensional topological insulators is crucial for the development of technological applications. Recently, an important step forward, namely, the experimental realization of a quantum point contact between helical edges, has been accomplished. We theoretically predict that such a quantum point contact, in the presence of a time periodic applied electric field, is characterized by a topological quantum phase transition in the Floquet spectrum. Moreover, we show that it is possible to detect this dynamical topological quantum phase transition by a bare conductance measurements.