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arXiv 1502.07080cond-mat.mes-hallcond-mat.str-el
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BiTeCl中可能的拓扑表面态的扫描隧道显微镜研究

Scanning tunneling microscopy study of the possible topological surface states in BiTeCl

Y. J. Yan, M. Q. Ren, X. Liu, Z. C. Huang, J. Jiang, Q. Fan, J. Miao, B. P. Xie, T. Zhang, D. L. Feng

摘要:

近年来,非中心对称碲化铋化合物如BiTeCl作为拓扑绝缘体的候选材料被研究。虽然一些光电子能谱研究表明BiTeCl是一种反转非对称拓扑绝缘体,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。本文报道了BiTeCl单晶表面态的低温扫描隧道显微镜研究。在低缺陷密度的碲终止表面上,在由这些状态的散射产生的准粒子干涉图案中发现了拓扑表面状态的强有力证据,无论是在散射矢量的各向异性还是在台阶边缘附近的干涉的快速衰减。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。我们的研究结果有助于解决目前的争议BiTeCl的拓扑性质。

英文摘要:

Recently, the non-centrosymmetric bismuth tellurohalides such as BiTeCl are being studied as possible candidates of 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 calculationsfailed to confirm the existence of topological surface states in BiTeCl so far. Therefore, the topological nature of BiTeCl requires further investigation. Here we report low temperature scanning tunneling microscopy study on the surface states of BiTeCl single crystals. On the tellurium-terminated surfaces with low defect density, strong evidences for topological surface states are found in the quasi-particle interference patterns generated by the scattering of these states, both in the anisotropy of the scattering vectors and the fast decay of the interference near step edges. Meanwhile, on samples with much higher defect densities, we observed surface states that behave differently. Our results help to resolve the current controversy on the topological nature of BiTeCl.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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