Spin-Orbit Coupling and Electronic Band Inversion in Bismuth-Based Half-Heusler Topological Compounds

International Journal of Physics | Vol. 4, No. 8, August 2013 | pp. 57–64

DOI: 10.46882/2013/IJP/000040

Research Article

Title: Spin-Orbit Coupling and Electronic Band Inversion in Bismuth-Based Half-Heusler Topological Compounds

Names of Authors: T. M. Nguyen¹, K. K. Suzuki²

Authors’ Affiliations: ¹Department of Physics, Vietnam National University, Hanoi 100000, Vietnam; ²Department of Physics, Graduate School of Science, Tohoku University, Sendai 180-8578, Japan

Abstract: Half-Heusler alloys have emerged as a versatile platform for exploring the intersection of topological states, superconductivity, and heavy-fermion physics. This study evaluates the electronic band structure and quantifies the spin-orbit coupling effects in bismuth-based Heusler compounds (LuPtBi and YPtBi). We performed fully relativistic density functional theory calculations including core-level corrections and customized electron correlation parameters. The calculated electronic structures demonstrate a distinct band inversion at the Gamma high-symmetry point of the Brillouin zone. In LuPtBi, the bismuth 6p states are shifted above the platinum 5d states, creating a negative band gap value of -0.42 eV. This configuration confirms the non-trivial topological character of the material. We verified the existence of topological surface states by computing the surface state density using the Green's function methodology on a semi-infinite crystal slab. The surface calculations show a well-defined Dirac cone intersecting the Fermi level with a high Fermi velocity of vF = 5.2 x 10^7 cm/s. The calculation of the Z2 topological invariant yields (1;000), classifying these intermetallic systems as strong topological insulators. These solid-state properties make these compounds promising materials for developing robust quantum computing components and low-power spintronic devices.

Keywords: Topological insulators; half-Heusler alloys; density functional theory; spin-orbit coupling; band inversion; Dirac cone

Manuscript Timeline: Received: April 15, 2013; Revised: June 02, 2013; Accepted: June 22, 2013; Published: August 19, 2013

Citation: Nguyen, T. M., & Suzuki, K. K. (2013). Spin-Orbit Coupling and Electronic Band Inversion in Bismuth-Based Half-Heusler Topological Compounds. International Journal of Physics, 4(8), 57–64.

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