Topological insulator homojunctions including magnetic layers: The example of n-p type (n-QLs Bi2Se3/Mn-Bi2Se3) heterostructures
Topological insulator homojunctions including magnetic layers: The example of n-p type (n-QLs Bi2Se3/Mn-Bi2Se3) heterostructures
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DOI：
10.1063/1.4954834
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发表时间：
2016-02
影响因子：
4
通讯作者：
M. Vališka;J. Warmuth;M. Michiardi;M. Vondráček;Arlette S. Ngankeu;V. Holý;V. Sechovský;G. Springholz;M. Bianchi;J. Wiebe;P. Hofmann;J. Honolka
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作者：
M. Vališka;J. Warmuth;M. Michiardi;M. Vondráček;Arlette S. Ngankeu;V. Holý;V. Sechovský;G. Springholz;M. Bianchi;J. Wiebe;P. Hofmann;J. Honolka
以Bi2Se_3及其掺锰相的同质结为例，研究了自旋自由度对绝缘体拓扑性质的影响。用分子束外延技术在掺锰的Bi2Se_3上生长了N个五层结构的Bi2Se_3，获得了0≤n≤_(30)QL，利用角度分辨光电子能谱等表面敏感技术，可以不受阻碍地监测其电子和拓扑性质的发展。随着n的增加，在Dirac点处由Mn引起的空位逐渐以沙漏的形式被填充，从而在n∼9qls处重新建立了一个拓扑表面态。我们的结果表明，由于n-p型界面的存在，导致了向上和向下的能带弯曲效应的竞争，这种界面可以独立地用于定制拓扑态和量子井态。
Homojunctions between Bi2Se3 and its Mn-doped phase are investigated as a sample geometry to study the influence of spin degrees of freedom on topological insulator properties. n quintuple layers of Bi2Se3 are grown on top of Mn-doped Bi2Se3 by molecular beam epitaxy for 0≤n≤30 QLs, allowing to unhamperedly monitor the development of electronic and topological properties by surface sensitive techniques like angle resolved photoemission spectroscopy. With increasing n, a Mn-induced gap at the Dirac point is gradually filled in an “hourglass” fashion to reestablish a topological surface state at n∼9 QLs. Our results suggest a competition of upward and downward band bending effects due to the presence of an n-p type interface, which can be used to tailor topological and quantum well states independently.