▎ 摘　　要

Spin-related thermoelectric effect in low-dimensional system has become a very important research filed in nanoelectronics and spintronics. In this work, we report a first principles calculation of spin-resolved Seebeck effect as well as transport properties in wedge-shaped graphene ribbon nanojunctions. A series of spin-resolved transmission dips are formed for the single channel transport due to the quasi-bound states induced by back scattering of electrons near the wedge-shape edges in the center of the junctions. Near the spin-resolved anti-resonant dips, large spin thermopower and spin figure of merits can be achieved. Moreover, by adjusting the chemical potential and temperatures of both leads, pure spin current without charge current can be obtained near the energies of transmission dips for each nanojunction. The proposed wedge-shaped graphene nanojunctions may have potential application as low-dimensional nanoscale thermoelectric devices.