Multiple crossing of Landau levels of two-dimensional fermions in double HgTe quantum wells

TL;DR

This study investigates Landau level crossings in double HgTe quantum wells, revealing complex quantum Hall behaviors and comparing experimental results with theoretical models.

Contribution

It provides the first detailed analysis of Landau level crossing patterns in double HgTe quantum wells, combining experimental magnetotransport data with theoretical calculations.

Findings

Numerous Landau level crossings observed in magnetotransport measurements.

Complex filling factor diagrams indicating multiple phase states.

Good agreement between experimental data and theoretical predictions.

Abstract

The double quantum well systems consisting of two HgTe layers separated by a tunnel-transparent barrier are expected to manifest a variety of phase states including two-dimensional gapless semimetal and two-dimensional topological insulator. The presence of several subbands in such systems leads to a rich filling factor diagram in the quantum Hall regime. We have performed magnetotransport measurements of the HgTe-based double quantum wells in both gapless and gapped state and observed numerous crossings between the Landau levels belonging to different subbands. We analyze the Landau level crossing patterns and compare them to the results of theoretical calculations.