Diluted ferromagnetic graphene by compensated n-p codoping

In this study, we propose a new approach, based on compensated n-p codoping, that can simultaneously address all the main shortcomings associated with single-element doping, effectively resulting in “diluted ferromagnetic graphene”. Our proposal is to deposit magnetic transitional metal (TM) atoms (such as Fe, Co, and Ni), acting as n-type dopants, onto already p-doped (e.g., by B) graphene. Through systematic first-principles calculations within density functional theory, we found that: (1) the electrostatic attraction between the n- and p-type dopants effectively enhances the adsorption of the TM adatoms and suppress their undesirable clustering, (2) the p-doping by B significantly enhances the magnetic moments of the TM adatoms, and (3) the compensated nature of the n-p codoping helps to preserve the Dirac nature of the charge carriers. Furthermore, through Monte Carlo simulations of a Heisenberg model with the essential magnetic coupling parameters obtained from the first-principles calculations, we found that Ni-B codoped graphene has a robust ferromagnetic order at experimentally feasible doping concentrations, with a Curie temperature as high as 212 K.