Band structure of a three-dimensional topological insulator quantum wire in the presence of a magnetic field
Band structure of a three-dimensional topological insulator quantum wire in the presence of a magnetic field
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DOI：
10.1088/0953-8984/28/27/275501
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发表时间：
2016-05
期刊：
影响因子：
--
通讯作者：
Zhe Liu;Liwei Jiang;Yisong Zheng
中科院分区：
文献类型：
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作者：
Zhe Liu;Liwei Jiang;Yisong Zheng
利用数值对角化方法计算了磁场作用下三维拓扑绝缘体量子线的电子结构。当量子阱的矩形截面具有大的纵横比时，量子阱可以被看作是具有侧表面的3DTI膜。我们的计算表明，非手征边缘态的出现，因为在侧表面的限制状态。这些态完全覆盖了朗道能级之间的价带区域，这合理地解释了相关实验工作中没有ν<−1的量子霍尔效应。在3DTI膜中，电子型带和空穴型带之间发生反转，这导致所谓的赝自旋霍尔效应。在具有正方形横截面的3DTI QW中，倾斜磁场可以在所有四个表面中建立定义良好的朗道能级。在这种情况下，量子霍尔边缘态局域在正方形的角落，其特征在于线性交叉的一维带分布。它们可以通过简单地旋转磁场在相邻的角之间移动。
By means of a numerical diagonalization approach, we calculate the electronic structure of a three-dimensional topological insulator (3DTI) quantum wire (QW) in the presence of a magnetic field. The QW can be viewed as a 3DTI film with lateral surfaces, when its rectangular cross section has a large aspect ratio. Our calculation indicates that nonchiral edge states emerge because of the confined states at the lateral surfaces. These states completely cover the valence band region among the Landau levels, which reasonably account for the absence of the ν<−1 quantum Hall effect in the relevant experimental works. In an ultrathin 3DTI film, inversion between the electron-type and hole-type bands occurs, which leads to the so-called pseudo-spin Hall effect. In a 3DTI QW with a square cross section, a tilting magnetic field can establish well-defined Landau levels in all four surfaces. In such a case, the quantum Hall edge states are localized at the square corners, characterized by the linearly crossing one-dimensional band profile. And they can be shifted between the adjacent corners by simply rotating the magnetic field.