Quantum spin Hall phase in stanene-derived overlayers on passivated SiC substrates.

We present atomic and electronic structure studies using first-principles calculations of two-dimensional topological insulators, stanene and fluorostanene, deposited on 4 H -SiC(0001) substrates. We demonstrate the stability of H- or F-passivated honeycomb crystals due to a van der Waals interaction between the adsorbate and substrate. Despite destroyed inversion symmetry and biaxial strain the calculations of the band structures and Z2 topological invariants predict that the quantum spin Hall (QSH) phase of stanene on H-passivated SiC as well as fluorostanene on H- and F-passivated SiC survives the interaction with the substrate. Our findings should serve as guidance for the epitaxial growth of tin-based QSH systems on wide-band-gap semiconductors. [ABSTRACT FROM AUTHOR]