Tuning electronic and thermoelectric properties of armchair graphene nanoribbon in the presence of electron phonon coupling

Abstract

Electronic and thermoelectric properties of armchair graphene nanoribbon taking into account the effects of interaction between electrons and Einstein phonons have been addressed. Specially we study the temperature dependence of thermal conductivity, density of states and specific heat of the structure. The effects of electron phonon coupling strength on thermal conductivity and thermoelectric electronic of the system have been studied. Green’s function method has been implemented to obtain electronic properties of the system in the context of Holstein Hamiltonian. One loop electronic self-energy of the Hamiltonian has been obtained in order to find interacting electronic Green’s function. The transport and thermoelectric properties of armchair graphene nanoribbon in the presence of electron phonon coupling can be readily found using interacting Green’s function based on Kubo formula. We find numerical results for chemical potential dependence of thermal conductivity and thermoelectric properties in the presence of Holstein phonons. Specially the behaviors of Seebeck coefficient, power factor function, figure of merit and Lorenz number of the system have been analyzed. Our results show turning on electron phonon coupling leads to reduction of band gap in density of states of the armchair nanoribbon.