论文标题
不对称与对称$ \ rm {hgte/cd_ {x} hg_ {1-x} te} $ double量子井：带宽度差距，没有电场
Asymmetric versus symmetric $\rm{HgTe/Cd_{x}Hg_{1-x}Te}$ double quantum wells: Band gap tuning without electric field
论文作者
论文摘要
我们以双重非对称$ \ rm {hgte/cd_ {x} hg_ {1-x} te} $沿$ [001] $方向生长的量子井中研究电子状态。子带是通过应用于8频段kane $ \ bf {k} \ cdot \ bf {p} $模型的信封功能近似计算的。双量子井的限制电势的不对称性导致间隙开口，在对称系统中不存在，在对称系统中只能由施加的电场诱导。带隙和子带受自旋轨道耦合的影响，这是限制电位不对称的结果。电子状和孔状状态主要限制在不同的量子井中，并且它们之间的增强杂交在有限的面内波形处打开了旋转依赖性的杂交间隙。我们表明，两个量子井的宽度和$ \ rm {cd_ {x} hg_ {1-x} te} $屏障的宽度的比率均可控制孔状状态和杂交差距之间的能量差距。能量子带显示显示出倒下的顺序，因此系统可能会出现非平凡的拓扑阶段。
We investigate the electron states in double asymmetric $\rm{HgTe/Cd_{x}Hg_{1-x}Te}$ quantum wells grown along the $[001]$ direction. The subbands are computed by means of the envelope function approximation applied to the 8-band Kane $\bf{k}\cdot\bf{p}$ model. The asymmetry of the confining potential of the double quantum wells results in a gap opening which is absent in the symmetric system where it can only be induced by an applied electric field. The band gap and the subbands are affected by spin-orbit coupling which is a consequence of the asymmetry of the confining potential. The electron-like and hole-like states are mainly confined in different quantum wells, and the enhanced hybridization between them opens a spin-dependent hybridization gap at a finite in-plane wavevector. We show that both the ratio of the widths of the two quantum wells and the mole fraction of the $\rm{Cd_{x}Hg_{1-x}Te}$ barrier control both the energy gap between the hole-like states and the hybridization gap. The energy subbands are shown to exhibit inverted ordering, and therefore a nontrivial topological phase could emerge in the system.
