Spin-thermoelectric transport in nonuniform strained zigzag graphene nanoribbons

Abstract

We study a nonuniform strain in zigzag graphene nanoribbons for producing the spin-thermoelectric effects,using the mean-field Hubbard approximation and a Green’s function approach. Our theoretical results showthat a sinusoidal-shaped inhomogeneous strain with electron-electron interaction could induce a different effecton each edge of zigzag nanoribbons and finally generate a spin semiconductor with a tunable spin-dependentband gap. The strength of strain also controls the magnitude of magnetization in each edge. Interestingly, purespin current and a giant spin Seebeck coefficient can be produced even at low values of strain by applying athermal gradient and without magnetic elements. These results pave a practical way toward improved design forspin-thermoelectric applications through strain engineering.