Spectral asymmetry induces a re-entrant quantum Hall effect in a topological insulator
Abstract
The band inversion of topological materials in three spatial dimensions is intimately connected to the parity anomaly of two-dimensional massless Dirac fermions. At finite magnetic fields, the parity anomaly reveals itself as a non-zero spectral asymmetry, i.e., a non-zero difference between the number of conduction and valence band Landau levels, due to the unpaired zero Landau level. Here, we realize this two-dimensional Dirac physics at a single surface of the three-dimensional topological insulator (Hg,Mn)Te. We observe an unconventional re-entrant quantum Hall effect that can be directly related to the occurrence of spectral asymmetry in a single topological surface state. The effect should be observable in any topological insulator where the transport is dominated by a single Dirac surface state.
Keywords
Cite
@article{arxiv.2402.05770,
title = {Spectral asymmetry induces a re-entrant quantum Hall effect in a topological insulator},
author = {Li-Xian Wang and Wouter Beugeling and Fabian Schmitt and Lukas Lunczer and Julian-Benedikt Mayer and Hartmut Buhmann and Ewelina M. Hankiewicz and Laurens W. Molenkamp},
journal= {arXiv preprint arXiv:2402.05770},
year = {2025}
}
Comments
13 pages, 10 figures, originally submitted version, includes supplementary material