Magnetothermoelectric properties of Al-Porphyrin sandwiched by graphene nanoribbon electrode based on quantum interference

Abstract

Rational design of single-molecular junction for efficient thermoelectric properties is a key prerequisite for thermoelectric conversion and fundamental challenge because of the existence of restrictive relationship between Seebeck coefficient and conductance. Inspired by the promising mechanism for promoting thermoelectric properties depended on spin-filter efficiency, magnetothermoelectric properties of aluminum porphyrin (Al-porphyrin) molecular junction have been investigated in contact with ferromagnetic graphene electrodes at different temperature. It is found that spin-resolved Seebeck coefficient is larger than charge-resolved Seebeck coefficient, leading to an excellent spin-resolved power factor about 0.3 pW/K2 at 0.25 eV for Al-porphyrin molecular junction. Ferromagnetic leads effectively realize thermal spin-filtering effect (SFE), which is induced by spin-resolved quantum interference (SQI) between graphene electrode and central nonmagnetic Al-porphyrin molecule. These results indicate the prospects of Al-porphyrin molecular junction applications in spin-caloritronics.