Thermal spin filtering, thermal spin switching and negative-differential-resistance in thermal spin currents in zigzag SiC nanoribbons.

Spin caloritronics with a combination of spintronics and thermoelectrics has potential applications in future information science and opens a new direction in the development of multi-functional materials. Based on density functional theory and the nonequilibrium Green's function method, we calculate thermal spin-dependent transport through a zigzag silicon carbide nanoribbon (ZSiCNR), which is a heterojunction consisting of a left electrode (ZSiC-2H1H) and right electrode terminated (ZSiC-1H1H) by hydrogen. Our results show that when the temperature in the left contact increases over a critical value, the thermal spin-down current increases remarkably from zero, while the thermal spin-up current remains zero in the total-temperature region, indicating that a perfect thermal spin filter together with a perfect spin switcher is obtained. Furthermore, the thermal spin current shows a negative differential resistance effect and quantum oscillation behaviors. These results suggest that the zigzag SiC nanoribbon proposed by us can be designed as a highly-efficient spin caloritronics device with multiple functionalities.