Temperature-controlled giant thermal magnetoresistance behaviors in doped zigzag-edged silicene nanoribbons

Abstract

Based on the nonequilibrium Green's function (NEGF) method combined with density functional theory (DFT), we investigate the spin-dependent thermoelectric transport properties of zigzag-edged silicene nanoribbons (ZSiNRs) doped by an Al–P bonded pair at different edge positions. For the ferromagnetic (FM) configuration, the strong quantum destructive interference effects between the localized states induced by the Al–P bonded pair and the side quantum states results in the appearance of spin-dependent transmission dips near the Fermi level. This fact leads to the simultaneous enhancement of the spin-filter efficiency and spin Seebeck coefficient at the Fermi level, while their signs are dependent on the doping positions. Moreover, for the antiferromagnetic (AFM) configuration, the spin-dependent transmission peaks with ordinary Lorentzian shapes near the Fermi level can be introduced by the Al–P bonded pair. Interestingly, a pure spin current in the doped AFM ZSiNRs can be achieved by modulating the temperature. In this case, the spin-filter efficiency can reach infinity, while the thermal magnetoresistance (TMR) between the FM and AFM configurations can also reach infinity.