Giant spin Seebeck effect in two-dimensional ferromagnetic CrI3 monolayer.

Spin Seebeck effect (SSE) is a key factor in the spin caloritronics field, and extensive studies have been performed for potential spin thermoelectric modulator device applications. However, the performance of spin current generation was not high enough, and this is due to the weak yield of the SSE. Despite the many studies for the SSE in bulk materials, no reports are available yet in the pure two-dimensional ferromagnetic material. Hereby, we investigated the SSE of the experimentally fabricated pure two-dimensional (2D) ferromagnetic CrI3 using the Boltzmann transport approach allowing diffusive scattering. We obtained a giant effective spin Seebeck effect of 1450 μV/K, and this value is at least 4 ~ 5 times larger than previously reported values in bulk systems. Therefore, our finding may suggest that the 2D CrI3 can be a potential material to open another perspective for the 2D materials in the spin caloritronics field.