Computational discovery of two-dimensional tetragonal group IV-V monolayers.

The two-dimensional (2D) hexagonal group IV-V family has attracted significant attention due to their unique properties and potential applications in electronics, spintronics, and photocatalysis. In this study, we report the discovery of a stable tetragonal allotrope, termed the Td4 phase, of 2D IV-V monolayers through a structural search utilizing an adaptive genetic algorithm. We investigate the geometric structures, structural stabilities, and band structures of the Td4-phase 2D IV-V monolayers (where IV = Si, Ge, Sn; V = P, As, Sb) based on the first-principles calculations.