Authors

Abstract

We have carried out diffusion Monte Carlo calculations for an A1B1-stacked bilayer blue phosphorene to find that it undergoes a semiconductor-metal transition asthe interlayer distance decreases. While the most stable bilayer structure is a semiconducting one with two monolayers coupled through weak van der Waals interaction, themetallic bilayer at a shorter interlayer distance is found to be only metastable. This is incontrast to a recent theoretical prediction based on random phase approximation thatthe metallic phase would be the most stable bilayer configuration of blue phosphorene.Our analysis of charge density distributions reveals that the metastable metallic phaseis induced by interlayer chemical bonding and intralayer charge redistributions. Thisstudy enriches our understanding of interlayer binding of a blue phosphorene and contributes to establishment of correct energetic order between its different phases, whichwill be essential in devising an experimental pathway for a metallic phosphorene.