International Journal of Physics | Vol. 6, No. 3, March 2015 | pp. 17–24
DOI: 10.46882/2015/IJP/000059
Research Article
Title: Topological Bound States and Robust Spin Transport in Two-Dimensional Quantum Spin Hall Insulators
Names of Authors: J. W. Park¹, M. T. Al-Saeed²
Authors’ Affiliations: ¹Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, South Korea; ²Department of Physics, Faculty of Science, Kuwait University, Safat, Kuwait
Abstract: Quantum spin Hall insulators provide an innovative pathway for developing low-power electronics by supporting backscattering-immune spin transport along their boundaries. This study designs and simulates topological bound states and robust spin transport within a two-dimensional honeycombed lattice of bismuth-pretreated silicon thin films. We computed the electronic band structures using the relativistic tight-binding method across the Brillouin zone. The strong intrinsic spin-orbit coupling breaks the electronic degeneracy at the Dirac valleys, creating a bulk topological band gap with a width of 0.18 eV. We calculated a non-zero spin Chern number of Cs = +1, verifying the non-trivial topological character of the system. To demonstrate transport robustness, we simulated spin-polarized electron wavepacket propagation past single-atom vacancies and line defect boundaries. The edge mode bypassed these structural obstacles with a high transmission efficiency of 99.4% ± 0.2%, showing zero backscattering due to time-reversal symmetry protections. These findings provide solid engineering targets for building backscattering-immune spintronic transistors, quantum data pathways, and integrated spin-logic circuits.
Keywords: Topological insulators; quantum spin Hall effect; spin-orbit coupling; tight-binding method; edge states; spintronics
Manuscript Timeline: Received: December 12, 2014; Revised: January 20, 2015; Accepted: February 07, 2015; Published: March 13, 2015
Citation: Park, J. W., & Al-Saeed, M. T. (2015). Topological Bound States and Robust Spin Transport in Two-Dimensional Quantum Spin Hall Insulators. International Journal of Physics, 6(3), 17–24.
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