A computational investigation of topological insulator Bi2Se3 film
A computational investigation of topological insulator Bi2Se3 film
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拓扑绝缘体 Bi2Se3 薄膜的计算研究
DOI：
10.1007/s11467-014-0441-1
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发表时间：
2014-08
期刊：
影响因子：
--
通讯作者：
Xue-Feng Wang
中科院分区：
文献类型：
--
作者：
Yi-Bin Hu;Yong-Hong Zhao;Xue-Feng Wang
拓扑绝缘体具有与普通绝缘体相似的体带隙和在其边缘或表面上的导电态，这些导电态通过自旋轨道耦合形成并受到时间反演对称性的保护。本文对三维拓扑绝缘体Bi_2Se_3薄膜在不同能量下的电子性质进行了理论分析。我们在狄拉克锥（-113 meV）周围选择五种不同的能量（-123，-75，0，180，350 meV）。当能量接近狄拉克锥时，波函数的性质与拓扑绝缘体的标志完美匹配。当能量远离狄拉克锥时，拓扑绝缘体的标志被打破，螺旋态消失。从计算结果中挖掘出螺旋态的电子性质。证实了螺旋态的自旋动量锁定。同时也揭示了布里渊区螺旋态的三重对称性。螺旋态的穿透深度是两个五重层，可以从层投影中识别。在布里渊区，各五重层上的电荷贡献与能量有关，沿沿着K和M方向有完全不同的行为。从轨道投影可以看出，螺旋态的最大电荷贡献是pz轨道，而py和px轨道上的电荷贡献具有二重对称性。
Topological insulators have a bulk band gap like an ordinary insulator and conducting states on their edge or surface which are formed by spin-orbit coupling and protected by time-reversal symmetry. We report theoretical analyses of the electronic properties of three-dimensional topological insulator Bi2Se3 film on different energies. We choose five different energies (−123, −75, 0, 180, 350 meV) around the Dirac cone (−113 meV). When energy is close to the Dirac cone, the properties of wave function match the topological insulator’s hallmark perfectly. When energy is far way from the Dirac cone, the hallmark of topological insulator is broken and the helical states disappear. The electronic properties of helical states are dug out from the calculation results. The spin-momentum locking of the helical states are confirmed. A 3-fold symmetry of the helical states in Brillouin zone is also revealed. The penetration depth of the helical states is two quintuple layers which can be identified from layer projection. The charge contribution on each quintuple layer depends on the energy, and has completely different behavior along K and M direction in Brillouin zone. From orbital projection, we can find that the maximum charge contribution of the helical states is pz orbit and the charge contribution on py and px orbits have 2-fold symmetry.
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影响因子：
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作者：
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通讯作者：
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影响因子：
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影响因子：
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作者：
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通讯作者：
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DOI：
10.1002/9783527681594.ch1
发表时间：
2015-02
期刊：
--
影响因子：
--
作者：
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通讯作者：
F. Ortmann;S. Roche;S. Valenzuela