Resistance fluctuation spectroscopy of thin films of 3D topological insulator BiSbTeSe1.6

Biswas, S and Gopal, RK and Singh, S and Kant, R and Mitra, C and Bid, A (2019) Resistance fluctuation spectroscopy of thin films of 3D topological insulator BiSbTeSe1.6. In: Applied Physics Letters, 115 (13).

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Abstract

Despite several years of studies, the origin of slow-kinetics of charge-carriers at the surface-states of strong topological insulators remains abstruse. In this article, we report on studies of charge dynamics of thin films of the 3-dimensional strong topological insulator material BiSbTeSe1.6 grown by pulsed laser deposition (PLD). The bulk of the films was insulating, making them suitable for transport studies of topological surface-states. Despite being disordered and granular, the films show definite signatures of the presence of topological surface-states with electronic transport coherence lengths comparable to those of high-quality grown films grown by molecular beam epitaxy (MBE). At high temperatures, the resistance fluctuations in these films were found to be dominated by trapping-detrapping of charge carriers from multiple defect-levels of the bulk. At low temperatures, fluctuations in the resistance of surface-states, arising due to the coupling of surface transport with defect dynamics in bulk, determine the noise. We thus confirm that the measured low-frequency fluctuations in these films, over the entire temperature range of 20 mK-300 K, are determined primarily by bulk defect density. The magnitude of noise was comparable to that measured on bulk-exfoliated films but was slightly higher than that in MBE grown films. Our studies establish PLD as a viable route to develop high-quality topological insulator materials. © 2019 Author(s).

Item Type:	Journal Article
Publication:	Applied Physics Letters
Publisher:	American Institute of Physics Inc.
Additional Information:	The copyright for this article belongs to American Institute of Physics Inc.
Keywords:	Antimony compounds; Bismuth compounds; Charge carriers; Electric insulators; Molecular beam epitaxy; Pulsed laser deposition; Selenium compounds; Surface resistance; Surface states; Tellurium compounds; Topological insulators; Topology, Electronic transport; High temperature; Low Frequency Fluctuations; Low temperatures; Multiple defects; Resistance fluctuation; Surface transport; Temperature range, Thin films
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	05 Jan 2023 11:42
Last Modified:	05 Jan 2023 11:42
URI:	https://eprints.iisc.ac.in/id/eprint/78796

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