Crystallinity of tellurium capping and epitaxy of ferromagnetic topological insulator films on SrTiO3

Thin films of topological insulators are often capped with an insulating layer since topological insulators are known to be fragile to degradation. However, capping can hinder the observation of novel transport properties of the surface states. To understand the influence of capping on the surface s...

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Main Authors:	Park, Jihwey, Soh, Yeong-Ah, Aeppli, Gabriel, Feng, Xiao, Ou, Yunbo, He, Ke, Xue, Qi-Kun
Format:	Online
Language:	English
Published:	Nature Publishing Group 2015
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4485028/

id	pubmed-4485028
recordtype	oai_dc
spelling	pubmed-44850282015-07-08 Crystallinity of tellurium capping and epitaxy of ferromagnetic topological insulator films on SrTiO3 Park, Jihwey Soh, Yeong-Ah Aeppli, Gabriel Feng, Xiao Ou, Yunbo He, Ke Xue, Qi-Kun Article Thin films of topological insulators are often capped with an insulating layer since topological insulators are known to be fragile to degradation. However, capping can hinder the observation of novel transport properties of the surface states. To understand the influence of capping on the surface states, it is crucial to understand the crystal structure and the atomic arrangement at the interfaces. Here, we use x-ray diffraction to establish the crystal structure of magnetic topological insulator Cr-doped (Bi,Sb)2Te3 (CBST) films grown on SrTiO3 (1 1 1) substrates with and without a Te capping layer. We find that both the film and capping layer are single crystal and that the crystal quality of the film is independent of the presence of the capping layer, but that x-rays cause sublimation of the CBST film, which is prevented by the capping layer. Our findings show that the different transport properties of capped films cannot be attributed to a lower crystal quality but to a more subtle effect such as a different electronic structure at the interface with the capping layer. Our results on the crystal structure and atomic arrangements of the topological heterostructure will enable modelling the electronic structure and design of topological heterostructures. Nature Publishing Group 2015-06-30 /pmc/articles/PMC4485028/ /pubmed/26123202 http://dx.doi.org/10.1038/srep11595 Text en Copyright © 2015, Macmillan Publishers Limited http://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Park, Jihwey Soh, Yeong-Ah Aeppli, Gabriel Feng, Xiao Ou, Yunbo He, Ke Xue, Qi-Kun
spellingShingle	Park, Jihwey Soh, Yeong-Ah Aeppli, Gabriel Feng, Xiao Ou, Yunbo He, Ke Xue, Qi-Kun Crystallinity of tellurium capping and epitaxy of ferromagnetic topological insulator films on SrTiO3
author_facet	Park, Jihwey Soh, Yeong-Ah Aeppli, Gabriel Feng, Xiao Ou, Yunbo He, Ke Xue, Qi-Kun
author_sort	Park, Jihwey
title	Crystallinity of tellurium capping and epitaxy of ferromagnetic topological insulator films on SrTiO3
title_short	Crystallinity of tellurium capping and epitaxy of ferromagnetic topological insulator films on SrTiO3
title_full	Crystallinity of tellurium capping and epitaxy of ferromagnetic topological insulator films on SrTiO3
title_fullStr	Crystallinity of tellurium capping and epitaxy of ferromagnetic topological insulator films on SrTiO3
title_full_unstemmed	Crystallinity of tellurium capping and epitaxy of ferromagnetic topological insulator films on SrTiO3
title_sort	crystallinity of tellurium capping and epitaxy of ferromagnetic topological insulator films on srtio3
description	Thin films of topological insulators are often capped with an insulating layer since topological insulators are known to be fragile to degradation. However, capping can hinder the observation of novel transport properties of the surface states. To understand the influence of capping on the surface states, it is crucial to understand the crystal structure and the atomic arrangement at the interfaces. Here, we use x-ray diffraction to establish the crystal structure of magnetic topological insulator Cr-doped (Bi,Sb)2Te3 (CBST) films grown on SrTiO3 (1 1 1) substrates with and without a Te capping layer. We find that both the film and capping layer are single crystal and that the crystal quality of the film is independent of the presence of the capping layer, but that x-rays cause sublimation of the CBST film, which is prevented by the capping layer. Our findings show that the different transport properties of capped films cannot be attributed to a lower crystal quality but to a more subtle effect such as a different electronic structure at the interface with the capping layer. Our results on the crystal structure and atomic arrangements of the topological heterostructure will enable modelling the electronic structure and design of topological heterostructures.
publisher	Nature Publishing Group
publishDate	2015
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4485028/
_version_	1613241575843823616

Crystallinity of tellurium capping and epitaxy of ferromagnetic topological insulator films on SrTiO3

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