Phys Chem Chem Phys. 2017 Oct 11;19(39):27132-27139. doi: 10.1039/c7cp05621d.

Edge-defect induced spin-dependent Seebeck effect and spin figure of merit in graphene nanoribbons.

Physical chemistry chemical physics : PCCP

Qing-Bo Liu, Dan-Dan Wu, Hua-Hua Fu

PMID: 28967009 DOI: 10.1039/c7cp05621d

Abstract

By using the first-principle calculations combined with the non-equilibrium Green's function approach, we have studied spin caloritronic properties of graphene nanoribbons (GNRs) with different edge defects. The theoretical results show that the edge-defected GNRs with sawtooth shapes can exhibit spin-dependent currents with opposite flowing directions by applying temperature gradients, indicating the occurrence of the spin-dependent Seebeck effect (SDSE). The edge defects bring about two opposite effects on the thermal spin currents: the enhancement of the symmetry of thermal spin-dependent currents, which contributes to the realization of pure thermal spin currents, and the decreasing of the spin thermoelectric conversion efficiency of the devices. It is fortunate that applying a gate voltage is an efficient route to optimize these two opposite spin thermoelectric properties towards realistic device applications. Moreover, due to the existence of spin-splitting band gaps, the edge-defected GNRs can be designed as spin-dependent Seebeck diodes and rectifiers, indicating that the edge-defected GNRs are potential candidates for room-temperature spin caloritronic devices.

Publication Types

• Journal Article