Ferromagnetism in chiral multilayer 2D semimetals

Abstract

We calculate the temperature dependent long-range magnetic coupling in the presence of dilute concentrations of random magnetic impurities in chiral multilayer two-dimensional semimetals, i.e., undoped intrinsic multilayer graphene. Assuming a carrier-mediated indirect RKKY exchange interaction among the well-separated magnetic impurities with the itinerant carriers mediating the magnetic interaction between the impurities, we investigate the magnetic properties of intrinsic multilayer graphene using an effective chiral Hamiltonian model. We find that due to the enhanced density of states in the rhombohedral stacking sequence of graphene layers, the magnetic ordering of multilayer graphene is ferromagnetic in the continuum limit. The ferromagnetic transition temperature is calculated using a finite-temperature self-consistent field approximation and found to be within the experimentally accessible range for reasonable values of the impurity-carrier coupling.