Spintronic properties of one-dimensional electron gas in graphene armchair ribbons

We have investigated, using effective mass approach (EMA), magnetic properties of a one-dimensional electron gas in graphene armchair ribbons when the electrons occupy only the lowest conduction subband. We find that magnetic properties of the one-dimensional electron gas may depend sensitively on the width of the ribbon. For ribbon widths Lx=3Ma0Lx=3Ma0, a critical point separates ferromagnetic and paramagnetic states while for Lx=(3M+1)a0Lx=(3M+1)a0 paramagnetic state is stable (M is an integer and a0 is the length of the unit cell). These width-dependent properties are a consequence of eigenstates that have a subtle width-dependent mixture of KK and K′K′ states, and can be understood by examining the wavefunction overlap that appears in the expression for the many-body exchange self-energy. Ferromagnetic and paramagnetic states may be used for spintronic purposes.

► The many-body exchange self-energy displays a width-dependence in AGR.
► Magnetic properties of electron in a AGR depends on the width of the ribbon.
► Ferromagnetic and paramagnetic states may be used for spintronic purposes.