Article Dans Une Revue Physical Review X Année : 2026

Quantum Coherent Transport of 1D Ballistic States in Second-Order Topological Insulator Bi4⁢Br4

Résumé

We investigate quantum transport in micrometer-sized single crystals of Bi$_4$Br$_4$, a material predicted to be a second-order topological insulator. 1D topological states with long phase coherence times are revealed via the modulation of quantum interferences with magnetic field and gate voltage. In particular, we demonstrate the existence of Aharanov-Bohm interference between 1D ballistic states several micrometers long, that we identify as phase-coherent hinge modes on neighbouring step edges at the crystal surface. These Aharanov-Bohm interferences are made possible by a disordered phase-coherent contact region, the existence of which is confirmed by STEM/EDX imaging of FIB lamellae. Their coherent nature modulates the transmission of the 1D edge states, leading to weak antilocalization and universal conductance fluctuations with surprisingly large characteristic fields and a strongly anisotropic behavior. These complementary experimental results provide a comprehensive, coherent description of quantum transport in Bi4⁢Br4 and establishes the material as belonging to the class of second-order topological insulators with topologically protected 1D ballistic states.

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Cite 10.5281/zenodo.17953562 Jeu de données Lefeuvre, J., & Deblock, R. (2025). Quantum Coherent Transport of 1D Ballistic States in Second Order Topological Insulator Bi4Br4 [Data set]. Zenodo. https://doi.org/10.5281/ZENODO.17953562

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hal-04970280 , version 1 (09-03-2026)

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Jules Lefeuvre, Masaru Kobayashi, Gilles Patriarche, Nathaniel Findling, David Troadec, et al.. Quantum Coherent Transport of 1D Ballistic States in Second-Order Topological Insulator Bi4⁢Br4. Physical Review X, 2026, 16 (1), pp.011031. ⟨10.1103/2bqq-t7ml⟩. ⟨hal-04970280⟩
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