少五重碲铋化物薄膜的晶体对称性破缺：在拓扑绝缘体纳米计量学中的应用
Crystal Symmetry Breaking in Few-Quintuple Bismuth Telluride Films: Applications in Nanometrology of Topological Insulators
摘要：
我们报告的“石墨烯”机械剥离的单晶碲化铋薄膜的厚度范围从几个纳米的范围到散装限制的显微拉曼光谱调查的结果。发现由于晶体对称性破缺，碲化铋晶体中不具有拉曼活性的光学声子模A_（1u）出现在原子结构的薄膜中。面外A1u和A1g模与面内Eg模的强度比随薄膜厚度的减小而增大。拉曼光谱随薄膜厚度的变化可用于鉴定具有少至五层厚度的碲化铋晶体，这对于拓扑绝缘体和热电应用是重要的。
英文摘要：
We report results of micro-Raman spectroscopy investigation of the "graphene-like" mechanically exfoliated single-crystal bismuth telluride films with the thickness ranging from a few-nm-range to bulk limit. It is found that the optical phonon mode A1u, which is not-Raman active in bulk bismuth telluride crystals, appears in the atomically-thin films due to crystal-symmetry breaking. The intensity ratios of the out-of-plane A1u and A1g modes to the in-plane Eg mode grow with decreasing film thickness. The evolution of Raman signatures with the film thickness can be used for identification of bismuth telluride crystals with the thickness of few-quintuple layers, which are important for topological insulator and thermoelectric applications.
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。
