First-principles study of magnetic properties in Mo-doped graphene

The geometric structure, electronic structure and magnetic properties of substitutionally Mo-doped graphene are studied based on first-principles calculations. Mo introduces a magnetic moment of 2 μB in graphene. The magnetic properties and band structure can be well understood using a hybridization model. Magnetic coupling between two Mo impurities is also discussed. Depending on the relative position of the two Mo impurities, the ground state of the system can be ferromagnetic, antiferromagnetic or paramagnetic. A Ruderman-Kittel-Kasuya-Yosida (RKKY)-like behavior is observed when the distance between Mo atoms is relatively large. However, when the distance between Mo atoms is rather small, the RKKY model is not suitable to describe the magnetic ordering due to their non-neglectable direct interactions. (paper)