Two-Dimensional Large Gap Topological Insulators with Large Rashba Spin-Orbit Coupling in Group-IV films

Abstract

Rashba spin orbit coupling in topological insulators has attracted much interest due to its exotic properties closely related to spintronic devices. The coexistence of nontrivial topology and giant Rashba splitting, however, has rare been observed in two-dimensional films, limiting severely its potential applications at room temperature. Here, we propose a series of inversion asymmetric group IV films, ABZ2, whose stability are confirmed by phonon spectrum calculations. The analyses of electronic structures reveal that they are intrinsic 2D TIs with a bulk gap as large as 0.74 eV, except for GeSiF2, SnSiCl2, GeSiCl2 and GeSiBr2 monolayers which can transform from normal to topological phases under appropriate tensile strains. Another prominent intriguing feature is the giant Rashba spin splitting with a magnitude reaching 0.15 eV, the largest value reported in 2D films. These results present a platform to explore 2D TIs for room temperature device applications.

31 pages and 11 figures

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Cited by in corpus (5)

• Optical absorption measurement of spin Berry curvature and spin Chern marker
• Fabry-Pérot resonant vortices and magnetoconductance in topological insulator constrictions with magnetic barriers
• Edge modes and Fabry-Perot Plasmonic Resonances in anomalous-Hall Thin Films
• On quasi-nodal spheres and the spin Hall effect: the case of YH3 and CaTe
• Spin-orbit effects on the spin and pseudospin polarization in ac-driven silicene