Probing embedded topological modes in bulk-like GeTe-Sb2Te3 heterostructures

Abstract The interface between topological and normal insulators hosts metallic states that appear due to the change in band topology. While topological states at a surface, i.e., a topological insulator-air/vacuum interface, have been studied intensely, topological states at a solid-solid interface...

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Autores principales:	Hisao Nakamura, Johannes Hofmann, Nobuki Inoue, Sebastian Koelling, Paul M. Koenraad, Gregor Mussler, Detlev Grützmacher, Vijay Narayan
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2020
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/d11c7ac399a3471a845d6e573600f5a8
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spelling	oai:doaj.org-article:d11c7ac399a3471a845d6e573600f5a82021-12-02T15:11:52ZProbing embedded topological modes in bulk-like GeTe-Sb2Te3 heterostructures10.1038/s41598-020-76885-72045-2322https://doaj.org/article/d11c7ac399a3471a845d6e573600f5a82020-12-01T00:00:00Zhttps://doi.org/10.1038/s41598-020-76885-7https://doaj.org/toc/2045-2322Abstract The interface between topological and normal insulators hosts metallic states that appear due to the change in band topology. While topological states at a surface, i.e., a topological insulator-air/vacuum interface, have been studied intensely, topological states at a solid-solid interface have been less explored. Here we combine experiment and theory to study such embedded topological states (ETSs) in heterostructures of GeTe (normal insulator) and $$\hbox {Sb}_2$$ Sb 2 $$\hbox {Te}_3$$ Te 3 (topological insulator). We analyse their dependence on the interface and their confinement characteristics. First, to characterise the heterostructures, we evaluate the GeTe-Sb $$_2$$ 2 Te $$_3$$ 3 band offset using X-ray photoemission spectroscopy, and chart the elemental composition using atom probe tomography. We then use first-principles to independently calculate the band offset and also parametrise the band structure within a four-band continuum model. Our analysis reveals, strikingly, that under realistic conditions, the interfacial topological modes are delocalised over many lattice spacings. In addition, the first-principles calculations indicate that the ETSs are relatively robust to disorder and this may have practical ramifications. Our study provides insights into how to manipulate topological modes in heterostructures and also provides a basis for recent experimental findings [Nguyen et al. Sci. Rep. 6, 27716 (2016)] where ETSs were seen to couple over thick layers.Hisao NakamuraJohannes HofmannNobuki InoueSebastian KoellingPaul M. KoenraadGregor MusslerDetlev GrützmacherVijay NarayanNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 10, Iss 1, Pp 1-10 (2020)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Hisao Nakamura Johannes Hofmann Nobuki Inoue Sebastian Koelling Paul M. Koenraad Gregor Mussler Detlev Grützmacher Vijay Narayan Probing embedded topological modes in bulk-like GeTe-Sb2Te3 heterostructures
description	Abstract The interface between topological and normal insulators hosts metallic states that appear due to the change in band topology. While topological states at a surface, i.e., a topological insulator-air/vacuum interface, have been studied intensely, topological states at a solid-solid interface have been less explored. Here we combine experiment and theory to study such embedded topological states (ETSs) in heterostructures of GeTe (normal insulator) and $$\hbox {Sb}_2$$ Sb 2 $$\hbox {Te}_3$$ Te 3 (topological insulator). We analyse their dependence on the interface and their confinement characteristics. First, to characterise the heterostructures, we evaluate the GeTe-Sb $$_2$$ 2 Te $$_3$$ 3 band offset using X-ray photoemission spectroscopy, and chart the elemental composition using atom probe tomography. We then use first-principles to independently calculate the band offset and also parametrise the band structure within a four-band continuum model. Our analysis reveals, strikingly, that under realistic conditions, the interfacial topological modes are delocalised over many lattice spacings. In addition, the first-principles calculations indicate that the ETSs are relatively robust to disorder and this may have practical ramifications. Our study provides insights into how to manipulate topological modes in heterostructures and also provides a basis for recent experimental findings [Nguyen et al. Sci. Rep. 6, 27716 (2016)] where ETSs were seen to couple over thick layers.
format	article
author	Hisao Nakamura Johannes Hofmann Nobuki Inoue Sebastian Koelling Paul M. Koenraad Gregor Mussler Detlev Grützmacher Vijay Narayan
author_facet	Hisao Nakamura Johannes Hofmann Nobuki Inoue Sebastian Koelling Paul M. Koenraad Gregor Mussler Detlev Grützmacher Vijay Narayan
author_sort	Hisao Nakamura
title	Probing embedded topological modes in bulk-like GeTe-Sb2Te3 heterostructures
title_short	Probing embedded topological modes in bulk-like GeTe-Sb2Te3 heterostructures
title_full	Probing embedded topological modes in bulk-like GeTe-Sb2Te3 heterostructures
title_fullStr	Probing embedded topological modes in bulk-like GeTe-Sb2Te3 heterostructures
title_full_unstemmed	Probing embedded topological modes in bulk-like GeTe-Sb2Te3 heterostructures
title_sort	probing embedded topological modes in bulk-like gete-sb2te3 heterostructures
publisher	Nature Portfolio
publishDate	2020
url	https://doaj.org/article/d11c7ac399a3471a845d6e573600f5a8
work_keys_str_mv	AT hisaonakamura probingembeddedtopologicalmodesinbulklikegetesb2te3heterostructures AT johanneshofmann probingembeddedtopologicalmodesinbulklikegetesb2te3heterostructures AT nobukiinoue probingembeddedtopologicalmodesinbulklikegetesb2te3heterostructures AT sebastiankoelling probingembeddedtopologicalmodesinbulklikegetesb2te3heterostructures AT paulmkoenraad probingembeddedtopologicalmodesinbulklikegetesb2te3heterostructures AT gregormussler probingembeddedtopologicalmodesinbulklikegetesb2te3heterostructures AT detlevgrutzmacher probingembeddedtopologicalmodesinbulklikegetesb2te3heterostructures AT vijaynarayan probingembeddedtopologicalmodesinbulklikegetesb2te3heterostructures
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Probing embedded topological modes in bulk-like GeTe-Sb2Te3 heterostructures

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