Bulk-surface coupling in dual topological insulator Bi1Te1 and Sb-doped Bi1Te1 single crystals via electron-phonon interaction

Mandal, S and Mallick, D and Bitla, Y and Ganesan, R and Kumar, PSA (2023) Bulk-surface coupling in dual topological insulator Bi1Te1 and Sb-doped Bi1Te1 single crystals via electron-phonon interaction. In: Journal of Physics Condensed Matter, 35 (28).

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Abstract

Recently, Bi1 Te1 has been proved to be a dual topological insulator (TI), a new subclass of symmetry-protected topological phases, and predicted to be higher order topological insulator (HOTI). Being a dual TI (DTI), Bi1Te1 is said to host quasi-1D surface states (SSs) due to weak TI phase and topological crystalline insulating SSs at the same time. On the other hand, HOTI supports topologically protected hinge states. So, B i 1 T e 1 is a unique platform to study the electrical signature of topological SS (TSS) of fundamentally different origins. Though there is a report of magneto-transport measurements on large-scale Bi1Te1 thin films, the Bi1Te1 single crystal is not studied experimentally to date. Even the doping effect in a DTI Bi1Te1 is missing in the literature. In this regard, we performed the perpendicular and parallel field magneto-transport measurement on the exfoliated microflake of Bi1Te1 and Sb-doped Bi1Te1 single crystals, grown by the modified Bridgmann method. Our metallic sample shows the weak anti-localization behavior analyzed by the multi-channel Hikami-Larkin-Nagaoka equation. We observed the presence of a pair of decoupled TSS. Further, we extracted the dephasing index (β) from temperature (T)-dependence of phase coherence length (Lϕ), following the power law equation (Lϕ ∝ T−β). The thickness-dependent value of β indicates the transition in the dephasing mechanism from electron-electron to electron-phonon interaction with the increase in thickness, indicating the enhancement in the strength of bulk-surface coupling. Sb-doped system shows weakened bulk-surface coupling, hinted by the reduced dephasing indices.

Item Type:	Journal Article
Publication:	Journal of Physics Condensed Matter
Publisher:	Institute of Physics
Additional Information:	The copyright of this article belongs to the Authors.
Keywords:	Antimony compounds; Bismuth compounds; Electric insulators; Electron-phonon interactions; Semiconductor doping; Single crystals; Tellurium compounds; Tensors; Topological insulators; Topology; Bulk surfaces; Dephasing; Dual topological insulator; High-order; Higher-order; Localisation; Sb-doped; Surface coupling; Topological insulators; Weak anti-localization; article; crystal; doping; phonon; thickness; Electrons
Department/Centre:	Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering Division of Physical & Mathematical Sciences > Physics
Date Deposited:	14 Jun 2023 06:26
Last Modified:	14 Jun 2023 06:26
URI:	https://eprints.iisc.ac.in/id/eprint/81856

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