Topological delocalization and tuning of surface channel separation in Bi2Se2Te Topological Insulator Thin films

Abstract The surface states of a 3D topological insulator (TI) exhibit topological protection against backscattering. However, the contribution of bulk electrons to the transport data is an impediment to the topological protection of surface states. We report the tuning of the chemical potential in...

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Autores principales:	Radha Krishna Gopal, Sourabh Singh, Arpita Mandal, Jit Sarkar, Chiranjib Mitra
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2017
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/812460526f2f47d094bfb0a35d5c68bc
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spelling	oai:doaj.org-article:812460526f2f47d094bfb0a35d5c68bc2021-12-02T12:32:52ZTopological delocalization and tuning of surface channel separation in Bi2Se2Te Topological Insulator Thin films10.1038/s41598-017-04458-22045-2322https://doaj.org/article/812460526f2f47d094bfb0a35d5c68bc2017-07-01T00:00:00Zhttps://doi.org/10.1038/s41598-017-04458-2https://doaj.org/toc/2045-2322Abstract The surface states of a 3D topological insulator (TI) exhibit topological protection against backscattering. However, the contribution of bulk electrons to the transport data is an impediment to the topological protection of surface states. We report the tuning of the chemical potential in the bulk in Bi2Se2Te TI thin films, pinning it near the center of the bulk band gap, thereby suppressing the bulk carriers. The temperature dependent resistance of these films show activated behavior down to 50 K, followed by a metallic transition at lower temperatures, a hallmark of robustness of TI surface states. Manifestation of topological protection and surface dominated transport is explained by 2D weak antilocalization phenomenon. We further explore the effect of surface to bulk coupling in TI in this work, which is captured by the number of effective conducting surface channels that participate in the transport. The presence of a single conducting channel indicates a strong surface to bulk coupling which is detrimental to purely topological transport. We demonstrate the decoupling of topological surface states on opposite surfaces of thin films, thereby suppressing the bulk transport. Our findings provide a deeper understanding of surface to bulk coupling along with topological transport behavior and their respective tunability.Radha Krishna GopalSourabh SinghArpita MandalJit SarkarChiranjib MitraNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 7, Iss 1, Pp 1-10 (2017)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Radha Krishna Gopal Sourabh Singh Arpita Mandal Jit Sarkar Chiranjib Mitra Topological delocalization and tuning of surface channel separation in Bi2Se2Te Topological Insulator Thin films
description	Abstract The surface states of a 3D topological insulator (TI) exhibit topological protection against backscattering. However, the contribution of bulk electrons to the transport data is an impediment to the topological protection of surface states. We report the tuning of the chemical potential in the bulk in Bi2Se2Te TI thin films, pinning it near the center of the bulk band gap, thereby suppressing the bulk carriers. The temperature dependent resistance of these films show activated behavior down to 50 K, followed by a metallic transition at lower temperatures, a hallmark of robustness of TI surface states. Manifestation of topological protection and surface dominated transport is explained by 2D weak antilocalization phenomenon. We further explore the effect of surface to bulk coupling in TI in this work, which is captured by the number of effective conducting surface channels that participate in the transport. The presence of a single conducting channel indicates a strong surface to bulk coupling which is detrimental to purely topological transport. We demonstrate the decoupling of topological surface states on opposite surfaces of thin films, thereby suppressing the bulk transport. Our findings provide a deeper understanding of surface to bulk coupling along with topological transport behavior and their respective tunability.
format	article
author	Radha Krishna Gopal Sourabh Singh Arpita Mandal Jit Sarkar Chiranjib Mitra
author_facet	Radha Krishna Gopal Sourabh Singh Arpita Mandal Jit Sarkar Chiranjib Mitra
author_sort	Radha Krishna Gopal
title	Topological delocalization and tuning of surface channel separation in Bi2Se2Te Topological Insulator Thin films
title_short	Topological delocalization and tuning of surface channel separation in Bi2Se2Te Topological Insulator Thin films
title_full	Topological delocalization and tuning of surface channel separation in Bi2Se2Te Topological Insulator Thin films
title_fullStr	Topological delocalization and tuning of surface channel separation in Bi2Se2Te Topological Insulator Thin films
title_full_unstemmed	Topological delocalization and tuning of surface channel separation in Bi2Se2Te Topological Insulator Thin films
title_sort	topological delocalization and tuning of surface channel separation in bi2se2te topological insulator thin films
publisher	Nature Portfolio
publishDate	2017
url	https://doaj.org/article/812460526f2f47d094bfb0a35d5c68bc
work_keys_str_mv	AT radhakrishnagopal topologicaldelocalizationandtuningofsurfacechannelseparationinbi2se2tetopologicalinsulatorthinfilms AT sourabhsingh topologicaldelocalizationandtuningofsurfacechannelseparationinbi2se2tetopologicalinsulatorthinfilms AT arpitamandal topologicaldelocalizationandtuningofsurfacechannelseparationinbi2se2tetopologicalinsulatorthinfilms AT jitsarkar topologicaldelocalizationandtuningofsurfacechannelseparationinbi2se2tetopologicalinsulatorthinfilms AT chiranjibmitra topologicaldelocalizationandtuningofsurfacechannelseparationinbi2se2tetopologicalinsulatorthinfilms
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Topological delocalization and tuning of surface channel separation in Bi2Se2Te Topological Insulator Thin films

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