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

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. Surprisingly, the one-dimensional (1D) edge channels, arising from the spectrum's inversion, demo...

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Main Authors: D. A. Khudaiberdiev, Z. D. Kvon, M. S. Ryzhkov, D. A. Kozlov, N. N. Mikhailov, A. Pimenov
Format: Article
Language:English
Published: American Physical Society 2025-05-01
Series:Physical Review Research
Online Access:http://doi.org/10.1103/PhysRevResearch.7.L022033
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author D. A. Khudaiberdiev
Z. D. Kvon
M. S. Ryzhkov
D. A. Kozlov
N. N. Mikhailov
A. Pimenov
author_facet D. A. Khudaiberdiev
Z. D. Kvon
M. S. Ryzhkov
D. A. Kozlov
N. N. Mikhailov
A. Pimenov
author_sort D. A. Khudaiberdiev
collection DOAJ
description 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. Surprisingly, 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. The weak magnetic field of 30 mT breaks the topological protection of 1D edge channels, thus turning the system into an ordinary Anderson insulator. At a field of 0.5 T, the 2D bulk electrons become delocalized, and the system transforms into a quantum Hall liquid.
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publisher American Physical Society
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series Physical Review Research
spelling doaj-art-df6d3622e3d64fc196d88a6359e61a522025-08-20T03:52:52ZengAmerican Physical SocietyPhysical Review Research2643-15642025-05-0172L02203310.1103/PhysRevResearch.7.L022033Two-dimensional topological Anderson insulator in a HgTe-based semimetalD. A. KhudaiberdievZ. D. KvonM. S. RyzhkovD. A. KozlovN. N. MikhailovA. PimenovWe 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. Surprisingly, 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. The weak magnetic field of 30 mT breaks the topological protection of 1D edge channels, thus turning the system into an ordinary Anderson insulator. At a field of 0.5 T, the 2D bulk electrons become delocalized, and the system transforms into a quantum Hall liquid.http://doi.org/10.1103/PhysRevResearch.7.L022033
spellingShingle D. A. Khudaiberdiev
Z. D. Kvon
M. S. Ryzhkov
D. A. Kozlov
N. N. Mikhailov
A. Pimenov
Two-dimensional topological Anderson insulator in a HgTe-based semimetal
Physical Review Research
title Two-dimensional topological Anderson insulator in a HgTe-based semimetal
title_full Two-dimensional topological Anderson insulator in a HgTe-based semimetal
title_fullStr Two-dimensional topological Anderson insulator in a HgTe-based semimetal
title_full_unstemmed Two-dimensional topological Anderson insulator in a HgTe-based semimetal
title_short Two-dimensional topological Anderson insulator in a HgTe-based semimetal
title_sort two dimensional topological anderson insulator in a hgte based semimetal
url http://doi.org/10.1103/PhysRevResearch.7.L022033
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