Crystallinity of tellurium capping and epitaxy of ferromagnetic topological insulator films on SrTiO3.
Crystallinity of tellurium capping and epitaxy of ferromagnetic topological insulator films on SrTiO3.
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SrTiO3 上碲覆盖的结晶度和铁磁拓扑绝缘体薄膜的外延
DOI：
10.1038/srep11595
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发表时间：
2015-06-30
影响因子：
4.6
通讯作者：
Xue QK
中科院分区：
文献类型：
--
作者：
Park J;Soh YA;Aeppli G;Feng X;Ou Y;He K;Xue QK
拓扑绝缘体的薄膜通常用绝缘层覆盖，因为众所周知，拓扑绝缘体很容易退化。然而，封顶会阻碍对表面态的新输运性质的观察。要了解封盖对表面态的影响，关键是要了解界面上的晶体结构和原子排列。本文用X射线衍射法研究了在有Te覆盖层和无Te覆盖层的SrTiO_3(111)衬底上生长的磁性拓扑绝缘体掺铬(Bi，Sb)_2Te_3(CBST)薄膜的晶体结构。我们发现薄膜和盖层都是单晶，薄膜的结晶质量与盖层的存在无关，但X射线引起CBST薄膜的升华，但盖层阻止了升华。我们的发现表明，不同的输运性质不能归因于较低的晶体质量，而是一种更微妙的效应，如与盖层界面处不同的电子结构。我们对拓扑异质结构的晶体结构和原子排列的研究结果将使电子结构的模拟和拓扑异质结构的设计成为可能。
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.
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影响因子：
3.7
作者：
Qi, Xiao-Liang;Hughes, Taylor L.;Zhang, Shou-Cheng
通讯作者：
Zhang, Shou-Cheng
影响因子：
64.8
作者：
Roushan, Pedram;Seo, Jungpil;Yazdani, Ali
通讯作者：
Yazdani, Ali
影响因子：
56.9
作者：
Zhang, Jinsong;Chang, Cui-Zu;Wang, Yayu
通讯作者：
Wang, Yayu
影响因子：
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作者：
Park, Jihwey;Soh, Yeong-Ah;Grey, Francois
通讯作者：
Grey, Francois
具有载流子无关长程铁磁序的磁掺杂拓扑绝缘体薄膜
影响因子：
29.4
作者：
Chang, Cui-Zu;Zhang, Jinsong;Xue, Qi-Kun
通讯作者：
Xue, Qi-Kun