Carrier density and magnetism in graphene zigzag nanoribbons

Abstract

The influence of carrier density on magnetism in a zigzag graphene nanoribbon\nis studied in a $\\pi$-orbital Hubbard-model mean-field approximation.\nDepartures from half-filling alter the magnetism, leading to states with charge\ndensity variation across the ribbon and parallel spin-alignment on opposite\nedges. Finite carrier densities cause the spin-density near the edges to\ndecrease steadily, leading eventually to the absence of magnetism. At low\ndoping densities the system shows a tendency to multiferroic order in which\nedge charges and spins are simultaneously polarized.\n