Giant Seebeck coefficient of the graphene/h-BN superlattices

The electronic structures and Seebeck coefficients of the graphene/h-BN superlattices which consist of zigzag graphene nanoribbons (ZGNRs) and zigzag BN nanoribbons (ZBNNRs) have been investigated using ab initio calculations based on the density functional theory. It has been shown that a ZGNR/ZBNNR marks up to 20 times larger in the Seebeck coefficient than graphene. The Seebeck coefficients of the superlattices increase with decreasing width of the constituent ZGNR. It has been revealed that the giant Seebeck coefficients of the superlattices stem from the so-called pudding mold band with a finite energy gap.