Electronic orbital angular momentum and magnetism of graphene

• Orbital angular momentum of graphene electrons is calculated.
• Orbital magnetic moment of graphene electrons is obtained.
• Variation in magnetization of graphene is calculated.
• Roles of different kinds of angular momentum are investigated.

Orbital angular momentum (OAM) of graphene electrons in a perpendicular magnetic field is calculated and corresponding magnetic moment is used to investigate the magnetism of perfect graphene. Variation in magnetization demonstrates its decrease with carrier-doping, plateaus in a large field, and de Haas–van Alphen oscillation. Regulation of graphene׳s magnetism by a parallel electric field is presented. The OAM originates from atomic-scale electronic motion in graphene lattice, and vector hopping interaction between carbon atomic orbitals is the building element. A comparison between OAM of graphene electrons, OAM of Dirac fermions, and total angular momentum of the latter demonstrates their different roles in graphene׳s magnetism. Applicability and relation to experiments of the results are discussed.