Meandering conduction channels and the tunable nature of quantized charge transport

Fuente: arXiv
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Autori principali: Douçot, Benoit, Kovrizhin, Dima, Moessner, Roderich
Natura: Preprint
Pubblicazione: 2024
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author Douçot, Benoit
Kovrizhin, Dima
Moessner, Roderich
author_facet Douçot, Benoit
Kovrizhin, Dima
Moessner, Roderich
contents The discovery of the quantum Hall effect founded the field of topological condensed matter physics. Its amazingly accurate quantisation of the Hall conductance, now enshrined in quantum metrology, is topologically protected: it is stable against any reasonable perturbation. Conversely, topological protection thus implies a form of censorship, as it completely hides any local information from the observer. The spatial distribution of the current in the sample is such a piece of information, which however has now become accessible thanks to spectacular experimental advances. It is an old question whether an original, and intuitively compelling, picture of the current flowing in a narrow channel along the sample edge is the physically correct one. Motivated by recent experiments $\textit{locally}$ imaging the quantized current flow in a Chern insulating (Bi, Sb)$_2$Te$_3$ heterostructure, [Rosen et al., PRL 129, 246602 (2022); Ferguson et.al, Nat. Mater. 22, 1100-1105 (2023)], we theoretically demonstrate the possibility of a broad `edge state' meandering away from the sample boundary deep into the sample bulk. Further, we show that varying experimental parameters permits continuously tuning between narrow edge states and meandering channels all the way to incompressible bulk transport. This accounts for various features observed in, and differing between, experiments. Overall, this underscores the robustness of topological condensed matter physics, but it also unveils a phenomenological richness hidden by topological censorship -- much of which we believe remains to be discovered.
format Preprint
id arxiv_https___arxiv_org_abs_2406_08548
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Meandering conduction channels and the tunable nature of quantized charge transport
Douçot, Benoit
Kovrizhin, Dima
Moessner, Roderich
Mesoscale and Nanoscale Physics
Materials Science
Quantum Gases
Strongly Correlated Electrons
The discovery of the quantum Hall effect founded the field of topological condensed matter physics. Its amazingly accurate quantisation of the Hall conductance, now enshrined in quantum metrology, is topologically protected: it is stable against any reasonable perturbation. Conversely, topological protection thus implies a form of censorship, as it completely hides any local information from the observer. The spatial distribution of the current in the sample is such a piece of information, which however has now become accessible thanks to spectacular experimental advances. It is an old question whether an original, and intuitively compelling, picture of the current flowing in a narrow channel along the sample edge is the physically correct one. Motivated by recent experiments $\textit{locally}$ imaging the quantized current flow in a Chern insulating (Bi, Sb)$_2$Te$_3$ heterostructure, [Rosen et al., PRL 129, 246602 (2022); Ferguson et.al, Nat. Mater. 22, 1100-1105 (2023)], we theoretically demonstrate the possibility of a broad `edge state' meandering away from the sample boundary deep into the sample bulk. Further, we show that varying experimental parameters permits continuously tuning between narrow edge states and meandering channels all the way to incompressible bulk transport. This accounts for various features observed in, and differing between, experiments. Overall, this underscores the robustness of topological condensed matter physics, but it also unveils a phenomenological richness hidden by topological censorship -- much of which we believe remains to be discovered.
title Meandering conduction channels and the tunable nature of quantized charge transport
topic Mesoscale and Nanoscale Physics
Materials Science
Quantum Gases
Strongly Correlated Electrons
url https://arxiv.org/abs/2406.08548