Scanning tunneling microscopy study of the possible topological surface states in BiTeCl
Scanning tunneling microscopy study of the possible topological surface states in BiTeCl
复制标题
DOI：
10.1088/0953-8984/27/47/475004
复制
发表时间：
2015-02
期刊：
影响因子：
--
通讯作者：
Yajun Yan;M. Ren;Xiaohan Liu;Zhangchao Huang;Junjie Jiang;Qun Fan;Jianmin Miao;B. Xie;F. Xiang;Xiaolin Wang;Tong Zhang;Dengguo Feng
中科院分区：
文献类型：
--
作者：
Yajun Yan;M. Ren;Xiaohan Liu;Zhangchao Huang;Junjie Jiang;Qun Fan;Jianmin Miao;B. Xie;F. Xiang;Xiaolin Wang;Tong Zhang;Dengguo Feng
最近，非中心对称的碲化铋卤化物如BiTeCl被研究作为拓扑绝缘体的可能候选者。虽然一些光电子能谱研究表明BiTeCl是一种反转不对称拓扑绝缘体，但其他研究表明它是一种具有Rashba分裂的正常半导体。同时，第一性原理计算至今未能证实BiTeCl中拓扑表面态的存在。因此，BiTeCl的拓扑性质需要进一步研究。在这里，我们报告了一个低温扫描隧道显微镜研究BiTeCl单晶的表面状态。在碲（Te）终止的表面具有相对较低的缺陷密度，拓扑表面状态的证据中观察到的准粒子干涉图案，无论是在各向异性的散射矢量和快速衰减的干涉附近的步骤边缘。同时，在具有更高缺陷密度的样品上，我们观察到不同的表面态。我们的研究结果可能有助于解决目前的争议BiTeCl的拓扑性质。
Recently, the non-centrosymmetric bismuth tellurohalides such as BiTeCl are being studied as possible candidates for topological insulators. While some photoemission studies showed that BiTeCl is an inversion asymmetric topological insulator, others showed that it is a normal semiconductor with Rashba splitting. Meanwhile, first-principle calculations have failed to confirm the existence of topological surface states in BiTeCl so far. Therefore, the topological nature of BiTeCl requires further investigation. Here we report a low-temperature scanning tunneling microscopy study on the surface states of BiTeCl single crystals. On the tellurium (Te) -terminated surfaces with relatively low defect density, evidence for topological surface states is observed in the quasi-particle interference patterns, both in the anisotropy of the scattering vectors and the fast decay of the interference near the step edges. Meanwhile, on the samples with much higher defect densities, we observed surface states that behave differently. Our results may help to resolve the current controversy on the topological nature of BiTeCl.