Chemical Functionalization of GaN Monolayer by Adatom Adsorption

The effect of adatom adsorption on the magnetism and band structure of graphene-like GaN monolayer at different coverages ( 1 / 8 and 1 / 2 ) was studied by spin-polarized density functional theory calculations. Generally speaking, though bare GaN monolayer is an indirect-band gap semiconductor, it could be turned to magnetic half-metal/metal by adsorbing F or N atoms at certain coverage. The Curie temperatures for half-metallic F-adsorbed and metallic N-adsorbed GaN monolayer are estimated to be about 480 and 420 K by Monte Carlo simulations, respectively. The induced magnetism mainly comes from the spin splitting of N 2p (2p z or 2p x /2p y ) orbitals. In the meantime, the adsorption of O atoms reduces the gap of the system. These excellent electronic and magnetic properties indicate great potential application of 2D GaN-based materials in future spintronics and optoelectronics.