Giant magnetoresistance and spin Seebeck coefficient in zigzag α-graphyne nanoribbons

We investigate the spin-dependent electric and thermoelectric properties of ferromagnetic zigzag alpha-graphyne nanoribbons (ZaGNRs) using density-functional theory combined with non-equilibrium Green's function method. A giant magnetoresistance is obtained in the pristine even-width ZaGNRs and can be as high as 106%. However, for the doped systems, a large magnetoresistance behavior may appear in the odd-width ZaGNRs rather than the even-width ones. This suggests that the magnetoresistance can be manipulated in a wide range by the dopants on the edges of ZaGNRs. Another interesting phenomenon is that in the B-and N-doped even-width ZaGNRs the spin Seebeck coefficient is always larger than the charge Seebeck coefficient, and a pure-spin-current thermospin device can be achieved at specific temperatures.