Spin-polarized edge modes and snake states in HgTe/CdTe quantum wells under an antisymmetric magnetic field
Spin-polarized edge modes and snake states in HgTe/CdTe quantum wells under an antisymmetric magnetic field
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反对称磁场下 HgTe/CdTe 量子阱中的自旋极化边缘模式和蛇态
DOI：
10.1103/physrevb.86.121403
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发表时间：
2012-09
影响因子：
3.7
通讯作者：
Sun Qing-Feng
中科院分区：
文献类型：
--
作者：
Zhang Ying-Tao;Zhai Feng;Qiao Zhenhua;Sun Qing-Feng
我们使用 Landauer-Buttiker 公式与格林函数技术相结合，证明了反对称磁场对倒置 HgTe 量子阱中边缘态的影响。在零场区域的任何宽度处，无间隙边缘模式出现在体带隙内部。通过计算波函数分布，我们发现（i）对于体能隙内的费米能量，边缘态作为量子自旋霍尔绝缘体沿着样品边界螺旋传播； (ii) 对于体能隙之外的费米能量，一对态沿着边界传播，而另一对“蛇态”出现并沿着中心零场区域反向传播。我们在数值上表明，后一种情况下的边缘模式对于短程安德森无序具有鲁棒性。
We demonstrate the effect of an antisymmetric magnetic field on the edge states in inverted HgTe quantum wells using the Landauer-Buttiker formula coupled with the Green's function technique. At any width of the zero-field region, gapless edge modes appear inside the bulk band gap. By calculating the wave function distribution, we find that (i) for Fermi energies inside the bulk gap, the edge states propagate helically along the sample boundaries as a quantum spin-Hall insulator; and (ii) for Fermi energies outside the bulk gap, a pair of states propagate along the boundaries, while the other pair of "snake states" appear and counterpropagate along the central zero-field region. We show numerically that the edge modes in the latter case are robust against the short-range Anderson disorder.