Quasi-Free-Standing Features of Stanene/Stanane on In Se and GaTe Nanosheets: A Computational Study

Two-dimensional tin and its iodized derivative, called stanene and stanane, are intriguing nanomaterials as quantum spin Hall (QSH) insulators. A recent experiment on stanene has found that the strong interaction from substrates will disturb the Dirac cones and cause a metallicity problem into stanene [F. Zhu et al. Nat. Mater. 2015, 14, 1020]. On the basis of van der Waals density functional calculations, we find that stanene and stanane can form commensurate van der Waals heterosheets with In Se and GaTe layers, which exhibit quasi-free-standing features with comparable spin-orbit coupling gaps to isolate values. Particularly, the supported stanane is still a large-gap QSH insulator, for which the substrates induce a tunable Rashba splitting that can be modulated by changing the interlayer distance of heterosheets. Our study demonstrates that layered III-VI chalcogenides are promising substrates for stanene and stanane, on which their intrinsics features can be well preserved for potential applications in topological materials and quantum manipulated devices.