Strain- and Fluorination-Induced Quantum Spin Hall Insulators in Blue Phosphorene: A First-Principles

By employing the density functional theory computations, we predict that the appropriate strain modification and surface fluorination of the monolayer blue phosphorene result in promising 2D topological insulators (TIs), which have sizable bulk gaps (284-554 meV) and great potential to be characterized and utilized at room temperature. The nontrivial topological phase was further convinced by the s-p band inversion, topological invariant v = 1, and edge states with a single Dirac-type crossing at the Gamma (or K) point. Our computational results provide some theoretical clues for the design of 2D TIs that can be experimentally realized from earth-abundant elements.