  We investigate the spin-dependent electric and thermoelectric properties of
ferromagnetic zigzag-graphyne nanoribbons (ZGNRs) using the density-functional
theory combined with the non-equilibrium Green's function method. A giant
magnetoresistance is obtained in the pristine even-width ZGNRs and can be as
high as 10e6 %. However, for the doped systems, a large magnetoresistance
behavior may appear in the odd-width ZGNRs rather than the even-width ones.
This suggests that the magnetoresistance can be manipulated in a wide range by
the dopants on edges of ZGNRs. Another interesting phenomenon is that in the B-
and N-doped even-width ZGNRs 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.
