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

Abstract

We present atomic and electronic structure studies using first-principles calculations of two-dimensional topological insulators, stanene and fluorostanene, deposited on $4H$-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 ${Z}_{2}$ 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.