Topological Valley States and Spin-Polarized Edge Transport in Fluorinated Tin Film Honeycomb Lattices

International Journal of Physics | Vol. 10, No. 1, January 2019 | pp. 1–8

DOI: 10.46882/2019/IJP/000105

Research Article

Title: Topological Valley States and Spin-Polarized Edge Transport in Fluorinated Tin Film Honeycomb Lattices

Names of Authors: J. W. Park¹, A. L. Silva²

Authors’ Affiliations: ¹Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, South Korea; ²Institute of Physics, Federal University of Rio Grande do Sul, Porto Alegre, Brazil

Abstract: Valleytronics provides an alternative pathway for low-power electronic hardware architectures by leveraging the valley degree of freedom to lock charge transport. This study models topological valley states and characterises spin-polarized edge transport in two-dimensional honeycombed lattices of fluorinated tin (stanene) films. We executed electronic band calculations using the relativistic tight-binding method across the hexagonal Brillouin zone. The combination of structural inversion asymmetry and strong intrinsic spin-orbit coupling breaks the valley degeneracy, opening a wide topological bulk bandgap of 0.24 eV. The system exhibits a non-zero valley Chern number of Cv = +1, which confirms non-trivial topological valley properties. To evaluate transport robustness, we simulated electron wavepacket propagation past point vacancies and sharp 60-degree boundary folds. The valley-polarized edge mode bypassed these structural obstacles with a high transmission efficiency of 99.6% ± 0.2%, demonstrating an absence of backscattering due to valley-contrast conservation rules. These findings provide solid engineering guidelines for building backscattering-immune valley-filter switches, quantum pathways, and integrated low-dissipation logic networks.

Keywords: Valleytronics; topological insulators; spin-orbit coupling; tight-binding method; edge states; stanene films

Manuscript Timeline: Received: October 12, 2018; Revised: November 27, 2018; Accepted: December 15, 2018; Published: January 14, 2019

Citation: Park, J. W., & Silva, A. L. (2019). Topological Valley States and Spin-Polarized Edge Transport in Fluorinated Tin Film Honeycomb Lattices. International Journal of Physics, 10(1), 1–8.

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