Armchair graphene nanoribbon-based spin caloritronics

Abstract

Armchair graphene nanoribbons are considered unsuitable for spin caloritronic applications, due to the lack of intrinsic magnetism. Inspired by the progress on fabricating carbon nanotubes with Janus edges Bets et al. (2019) [26], we construct graphene nanoribbons with Janus edges, where one edge is armchair type and the other one possesses triangular protrusions with zigzag-armchair or zigzag-zigzag sub-edges. By first-principles calculations, Spin Seebeck effect is found. Further analysis shows that, it is resulted from the difference of Fermi distributions between the two electrodes, which is triggered by temperature difference, and the peculiar transmission spectra, where two transmission peaks with opposite spins reside discretely on both sides of EF. These two peaks are contributed by the corresponding bands with opposite spins above and below EF respectively, which are induced by the sub-edges. We believe our findings would be useful in developing graphene-based spin caloritronics.