Dephasing effect promotes the appearance of quantized Hall plateaus

TL;DR

This paper demonstrates that dephasing effects can facilitate the emergence of quantized Hall plateaus in topological systems, even when quantum coherence is initially suppressed, highlighting a new aspect of topological phenomena.

Contribution

It reveals that dephasing promotes the appearance of quantum Hall plateaus, contrasting with the traditional view that coherence is essential for their formation.

Findings

Dephasing reduces Hall resistance and induces QH plateaus.

Perfect coherence with imperfect leads prevents plateau formation.

Similar effects observed in quantum anomalous Hall systems.

Abstract

The quantum Hall effect (QHE) is a topologically protected phenomenon which has been observed in various systems. In experiments, the size of Hall bar device to realize the QHE is generally much larger than the phase coherence length, in which the quantum coherence of electrons is destroyed. Here, we theoretically study the influence of dephasing effect on the quantized Hall (QH) plateaus. We find that the QH plateau disappears in perfectly quantum coherent systems if the coupling between leads and central region is imperfect. The Hall resistance is very large and strongly oscillates instead of presenting the QH plateau in this case. However, by introducing the dephasing, the Hall resistance decreases and the QH plateau appears gradually. Similar results can also be observed for the quantum anomalous Hall effect. Our results propose that dephasing effect promotes the appearance of QH plateaus, which opens a new topic of the dephasing effect on topological systems.