  The electronic structure and conductance of substitutionally edge-doped
zigzag silicene nanoribbons (ZSiNRs) are investigated using the nonequilibrium
Green's function method combined with the density functional theory. Two-probe
systems of ZSiNRs in both ferromagnetic and antiferromagnetic states are
considered. Doping effects of elements from groups III and V, in a parallel or
antiparallel magnetic configuration of the two electrodes, are discussed.
Switching on and off the external magnetic field, we may convert the metallic
ferromagnetic ZSiNRs into insulating antiferromagnetic ZSiNRs. In the
ferromagnetic state, even- or odd-width ZSiNRs exhibit a drastically different
magnetoresistance. In an odd-width edge-doped ZSiNR a large magnetoresistance
occurs compared to that in a pristine ZSiNR. The situation is reversed in
even-width ZSiNRs. These phenomena result from the drastic change of the
conductance in the antiparallel configuration.
