Spin thermoelectric effects of new-style one-dimensional carbon-based nanomaterials

Based on first-principles methods, the authors of this paper investigate spin thermoelectric effects of one-dimensional spin-based devices consisting of zigzag-edged graphene nanoribbons (ZGNRs), carbon chains and graphene nanoflake. It is found that the spin-down transmission function is suppressed to zero, while the spin-up transmission function is about 0.25. Therefore, an ideal half-metallic property is achieved. In addition, the phonon thermal conductance is obviously smaller than the electronic thermal conductance. Meantime, the spin Seebeck effects are obviously enhanced at the low-temperature regime (about 80K), resulting in the fact that spin thermoelectric figure of merit can reach about 40. Moreover, the spin thermoelectric figure of merit is always larger than the corresponding charge thermoelectric figure of merit. Therefore, the study shows that they can be used to prepare the ideal thermospin devices.