Chirality and correlations in the spontaneous spin-valley polarization of rhombohedral multilayer graphene

Abstract

We investigate the total energies of spontaneous spin-valley polarized states in bi-, tri-, and tetralayer rhombohedral graphene where the long-range Coulomb correlations are accounted for within the random phase approximation. Our analysis of the phase diagrams for varying carrier doping and perpendicular electric fields shows that the exchange interaction between chiral electrons is the main driver of spin-valley polarization, while the presence of Coulomb correlations brings the flavor polarization phase boundaries to carrier densities close to the complete filling of the Mexican hat shape top at the Dirac points. We find that the tendency towards spontaneous spin-valley polarization is enhanced with the chirality of the bands and therefore with increasing number of layers.