Crossover from gapped-to-gapless Dirac surface states in magnetic topological insulator MnBi2Te4

Rastogi, G and Mohapatra, A and Mishra, P and Mandal, S and Kulkarni, R and Ganesan, R and Thamizhavel, A and Anil Kumar, PS (2024) Crossover from gapped-to-gapless Dirac surface states in magnetic topological insulator MnBi2Te4. In: Journal of Physics Condensed Matter, 8 (85703).

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Abstract

Intrinsic magnetic topological insulators (MTIs) host exotic topological phases such as quantized anomalous Hall insulating phase, arising due to the large magnetic exchange gap. However, the interplay of magnetism and topology in these systems in different temperature regimes remains elusive. In this work, we present the logarithmic temperature-dependence of conductivity for sub-100 nm thick exfoliated flakes of MTI MnBi2Te4 in the presence of out-of-plane magnetic fields and extracted the linear slope, κ. We observed a characteristic change, � κ � � 0.5 in the low-temperature regime, indicating the gapped Dirac surface state according to Lu-Shen theory. We also report the recovery of topological properties in the system via the weak-antilocalization effect in the vicinity of antiferromagnetic to paramagnetic transition and in the paramagnetic regime. Hikami-Larkin-Nagaoka analysis suggested the presence of topological surface states. Therefore, our study helps in understanding how intrinsic magnetism masks topological properties in an MTI as long as magnetic ordering persists. © 2023 IOP Publishing Ltd.

Item Type:	Journal Article
Publication:	Journal of Physics Condensed Matter
Publisher:	Institute of Physics
Additional Information:	The copyright for this article belongs to Institute of Physics.
Keywords:	Antiferromagnetism; Bismuth compounds; Electric insulators; Manganese compounds; Paramagnetism; Tellurium compounds; Temperature distribution; Topological insulators; Topology, Insulating phase; Logarithmic temperature; Magnetic exchange; Magnetic topological insulator; Spin-flop transitions; Temperature dependence; Temperature regimes; Topological insulators; Topological phase; Topological properties, Surface states
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	28 Feb 2024 11:46
Last Modified:	28 Feb 2024 11:46
URI:	https://eprints.iisc.ac.in/id/eprint/83701

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