Landau Quantization and the Thickness Limit of Topological Insulator Thin Films of Sb2Te3
Landau Quantization and the Thickness Limit of Topological Insulator Thin Films of Sb2Te3
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Sb2Te3 拓扑绝缘体薄膜的朗道量子化和厚度极限
DOI：
10.1103/physrevlett.108.016401
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发表时间：
2012-01-03
影响因子：
8.6
通讯作者：
Xue, Qi-Kun
中科院分区：
文献类型：
--
作者：
Jiang, Yeping;Wang, Yilin;Xue, Qi-Kun
报道了用低温扫描隧道显微镜对分子束外延生长的Sb_2Te_3薄膜进行朗道量子化的实验观察。与以往报道的系统不同，Sb_2Te_3拓扑绝缘体中的朗道量子化对薄膜中的本征替位缺陷不敏感。结果，实现了2D无质量狄拉克费米子系统表面态近乎完美的线性能量色散。我们证明了四个五重层是作为3D拓扑绝缘体的Sb 2Te 3薄膜的厚度极限。朗道能级展宽的机制进行了讨论的增强准粒子寿命。
We report the experimental observation of Landau quantization of molecular beam epitaxy grown Sb2Te3 thin films by a low-temperature scanning tunneling microscope. Different from all the reported systems, the Landau quantization in a Sb2Te3 topological insulator is not sensitive to the intrinsic substitutional defects in the films. As a result, a nearly perfect linear energy dispersion of surface states as a 2D massless Dirac fermion system is achieved. We demonstrate that four quintuple layers are the thickness limit for a Sb2Te3 thin film being a 3D topological insulator. The mechanism of the Landau-level broadening is discussed in terms of enhanced quasiparticle lifetime.