Dissipation and dephasing in quantum Hall interferometers

TL;DR

This paper investigates how non-equilibrium conditions in quantum Hall interferometers cause inevitable dissipation and dephasing, affecting topological protection and quantum Hall plateaus, with implications for device design.

Contribution

It demonstrates the role of non-equilibrium effects in dissipation and dephasing in quantum Hall interferometers using numerical simulations, revealing their impact on topological states.

Findings

Dissipation occurs due to inelastic scattering in non-equilibrium edge states.

Dephasing influences the competition between Aharonov-Bohm interference and quantum Hall plateaus.

Optimal dephasing can enhance quantum Hall plateaus.

Abstract

In recent years, counter-intuitive results have shown that the quantum Hall edge states with topological protection can be dissipative. In this paper, we point out that the non-equilibrium nature of edge states in quantum Hall interferometers leads to inevitable dissipation. We consider a graphene interferometer operating in the integer quantum Hall regime and simulate the inelastic scattering that causes both dissipation and dephasing in the interferometer using non-equilibrium Green's function and virtual leads. We describe the dissipation process with the numerical results of the spatial distribution of heat generation and the evolution of electron energy distribution. In addition, with the enhancement of dephasing, a competition between Aharonov-Bohm interference and topologically protected quantized Hall plateaus is observed in the oscillations and fluctuations of the Hall resistances. At a suitable dephasing strength, quantum Hall plateaus can be promoted by dephasing. Our results not only give clues for the design of dissipation-free devices but also provide a platform for studying the non-equilibrium relaxation and the dissipation mechanism of topological states.