Two-dimensional topological Anderson insulator in a HgTe-based semimetal

Fuente: arXiv
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Main Authors: Khudaiberdiev, D. A., Kvon, Z. D., Ryzhkov, M. S., Kozlov, D. A., Mikhailov, N. N., Pimenov, A.
Format: Preprint
Published: 2024
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author Khudaiberdiev, D. A.
Kvon, Z. D.
Ryzhkov, M. S.
Kozlov, D. A.
Mikhailov, N. N.
Pimenov, A.
author_facet Khudaiberdiev, D. A.
Kvon, Z. D.
Ryzhkov, M. S.
Kozlov, D. A.
Mikhailov, N. N.
Pimenov, A.
contents We report the experimental observation of Anderson localization in two-dimensional (2D) electrons and holes in the bulk of HgTe quantum wells with a semimetallic spectrum and under strong disorder. In contrast, the one-dimensional (1D) edge channels, arising from the spectrum's inversion, demonstrate remarkable robustness against disorder due to topological protection. Strong disorder induces a mobility gap in the bulk, enabling access to the 1D edge states and thereby realizing the two-dimensional topological Anderson insulator (TAI) state. Nonlocal transport measurements confirm the emergence of topologically protected edge channels. The TAI state appears to be very sensitive to an external magnetic field applied perpendicular to the sample. Firstly, a small magnetic field of 30mT breaks the topological protection of 1D edge channels, thus turning the system into an ordinary Anderson insulator. Secondly, the magnetic field of 0.5T delocalizes 2D bulk electrons, transforming the system into a quantum Hall liquid.
format Preprint
id arxiv_https___arxiv_org_abs_2410_23564
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Two-dimensional topological Anderson insulator in a HgTe-based semimetal
Khudaiberdiev, D. A.
Kvon, Z. D.
Ryzhkov, M. S.
Kozlov, D. A.
Mikhailov, N. N.
Pimenov, A.
Mesoscale and Nanoscale Physics
We report the experimental observation of Anderson localization in two-dimensional (2D) electrons and holes in the bulk of HgTe quantum wells with a semimetallic spectrum and under strong disorder. In contrast, the one-dimensional (1D) edge channels, arising from the spectrum's inversion, demonstrate remarkable robustness against disorder due to topological protection. Strong disorder induces a mobility gap in the bulk, enabling access to the 1D edge states and thereby realizing the two-dimensional topological Anderson insulator (TAI) state. Nonlocal transport measurements confirm the emergence of topologically protected edge channels. The TAI state appears to be very sensitive to an external magnetic field applied perpendicular to the sample. Firstly, a small magnetic field of 30mT breaks the topological protection of 1D edge channels, thus turning the system into an ordinary Anderson insulator. Secondly, the magnetic field of 0.5T delocalizes 2D bulk electrons, transforming the system into a quantum Hall liquid.
title Two-dimensional topological Anderson insulator in a HgTe-based semimetal
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2410.23564