Tuning the electronic and magnetic properties of porous graphene-like carbon nitride through 3d transition-metal doping

Abstract

We present a density-functional-theory study of the recently synthesized graphene-like carbon nitride monolayer (C2N) with transition metal atom (TM = Fe, Co and Ni) doping. We find that for three elements, the TM-C2N binding is strong and covalent in nature. While the pristine C2N is a semiconductor with non-magnetism at the ground state, the TM-C2N complexes exhibit metal characteristic and is spin-polarized. Particularly, a Fe atom on C2N can induce 3.91 μB magnetic moment with ferromagnetic coupling. For Co and Ni, smaller magnetic moment is observed with weaker coupling or even no coupling. The spin-polarization can be understood in the local-orbital picture, involving hybridizations of nitrogen’s pz orbital with the 3d orbitals of metal. The work function of C2N can be effectively modulated by metal doping from 5.25 eV for pristine C2N to a range of 3.85–4.15 eV for doped ones. Our results indicate that the properties of C2N layer can be effectively modulated by chemical doping and the co-realization of metallic and ferromagnetic properties in doped C2N might find broad applications in the design of nanoscale electronic and spintronic devices.