Unraveling the Mechanism of Doping Borophene.

We elucidate the doping mechanism of suitable elements into borophene with first-principles density functional theory calculation. During doping with nitrogen (N), the sp 2 orbitals are responsible for arranging themselves to accommodate the electron of the N atom. Doping dramatically changes structure and electronic properties from corrugated and metallic borophene to flat and insulating h-BN with 100 % N-doping. We extend the mechanism of N-doping in borophene to doping of non-metallic and metallic ad-atoms on borophene. Our findings will help to design boron-based 2D materials.