Stain-Induced Band Inversion and Topological Nontriviality in Antimonene

Antimonene is a novel two-dimensional (2D) semiconducting material of group V elements proposed in a recent literature [Zhang et al., Angew. Chem. Int. Ed. 54, 1-5 (2015)]. Using first-principles calculations, we demonstrated that the buckled configuration of antimonene enables it sustain large tensile strain up to 20%. Band inversion takes place in the vicinity of the Gamma point as the tensile strain is larger than 14.5%, leading to six tilted Dirac cones in the Brillouin zone. Spin-orbital coupling (SOC) effect opens up a topologically nontrivial bulk band gap at the Dirac points, exhibiting the features of 2D topological insulators characterized by a nonzero Z2 topological invariant. The tunable bulk band gap, 101-560 meV, make the antimonene a promising candidate material for achieving quantum spin Hall effect (QSH) at high temperatures which meet the requirement of future electronic devices with low power consumption.