Khomitsky D V, Konakov A A, Lavrukhina E A
Department of Physics, National Research Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia.
J Phys Condens Matter. 2022 Aug 4;34(40). doi: 10.1088/1361-648X/ac8407.
A model of bound state formation from the delocalized edge states of 2D topological insulator (TI) is derived by considering the effects of magnetic barriers attached to the edge of the HgTe/CdTe quantum well. The resulting structure has a spatial form of 1D quantum dot (QD) with variable number of bound states depending on barrier parameters. The spatial profile of exchange interaction between the edge states and barriers is derived from the interaction with single impurity magnetic moment and is generalized for the barrier bulk structure formed by ensemble of impurities. The resulting Hamiltonian is studied as a function of barrier parameters including their strength and orientation of the magnetic moments. It is shown that for parallel magnetization of two barriers at least two discrete levels are formed regardless of the barrier strength. For antiparallel magnetization at least a single bound state is formed for any strength of the barriers. Our results may help in design of novel types of QDs based on TIs.
通过考虑附着在HgTe/CdTe量子阱边缘的磁垒的影响，推导了二维拓扑绝缘体（TI）的离域边缘态形成束缚态的模型。所得结构具有一维量子点（QD）的空间形式，其束缚态数量可变，具体取决于垒参数。边缘态与磁垒之间交换相互作用的空间分布是从与单个杂质磁矩的相互作用推导出来的，并推广到由杂质集合形成的磁垒体结构。研究了所得哈密顿量作为垒参数的函数，包括其强度和磁矩方向。结果表明，对于两个磁垒的平行磁化，无论磁垒强度如何，至少会形成两个离散能级。对于反平行磁化，对于任何强度的磁垒，至少会形成一个束缚态。我们的结果可能有助于基于拓扑绝缘体设计新型量子点。
