Confined states and spin polarization on a topological insulator thin film modulated by an electric potential |
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Authors: | Liu Yi-Man Shao Huai-Hua Zhou Xiao-Ying Zhou Guang-Hui |
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Affiliation: | Department of Physics and Key Laboratory for Low-Dimensional Structures and Quantum Manipulation (Ministry of Education), Hunan Normal University, Changsha 410081, China |
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Abstract: | We study the electronic structure and spin polarization of the surface states of a three-dimensional topological insulator thin film modulated by an electrical potential well. By routinely solving the low-energy surface Dirac equation for the system, we demonstrate that confined surface states exist, in which the electron density is almost localized inside the well and exponentially decayed outside in real space, and that their subband dispersions are quasilinear with respect to the propagating wavevector. Interestingly, the top and bottom surface confined states with the same density distribution have opposite spin polarizations due to the hybridization between the two surfaces. Along with the mathematical analysis, we provide an intuitive, topological understanding of the effect. |
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Keywords: | topological insulator thin film electronic structure spin polarization electric potential |
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