Boronated holey graphene: a case of 2D ferromagnetic metal

In search of new candidates for two-dimensional ferromagnets, we consider boronated monolayer holey graphene (C₂B), akin to recently synthesized and extensively studied nitrogenated monolayer holey graphene (C₂N). In contrast to C₂N which is semiconducting and nonmagnetic, our first-principles calculations show that C₂B is metallic and ferromagnetic. The microscopic origin of this interesting behavior is found to be related to the hole doping of π-π* network of C-B which produces metallicity while the unpaired electron on the dangling bond of sp² hybridized state of two-coordinated B produces magnetism. Calculated cohesive energy of boronated holey graphene indicates that the formation of this structure is energetically feasible as is the case with its nitrogenated counterpart. The dynamic and thermal stability of the predicted boronated holey graphene are checked in terms of phonon calculations and finite temperature molecular dynamics simulations. We further investigate the electronic and magnetic properties of embedded transition-metal single atom and pairs on C₂B and C₂N structures.