Promising spin caloritronics and spin diode effects based on 1T-FeCl2 nanotube devices

Spin caloritronics, which combines thermoelectric effects and spintronics, has received more and more attention as a feasible way to achieve lower-energy consumption and improved performance in thermal energy conversion devices. Although much research has focused on 2D materials recently, the side effects and low spin polarization cause a decrease in the thermoelectric characteristic. These problems could be easily solved in 1D nanostructures associated with bipolar magnetic semiconductors. Motivated by a recent synthesis of monolayer 1T-FeCl2 with complete spin polarization, we investigate the temperature-driven and bias-voltage spin transport properties based on the 1T-FeCl2 nanotube by using density functional theory combined with the nonequilibrium Green's function method. The spin filtering effect, negative differential resistance and spin Seebeck effect are found in the 1T-FeCl2 homogeneous nanotubes; the spin diode effect appears in the 1T-FeCl2 heterogeneous nanotubes. These distinct features suggest the potential applications of 1T-FeCl2 nanotubes in spintronic devices and spin caloritronics devices.