▎ 摘　　要

Transport through a nano-device in the presence of electron-phonon interaction has been studied by using unitary-transformation scheme together with the non-equilibrium Green's function formalism. The non-interacting Hamiltonian is written within the tight binding model and left/right electrodes are described in wide-band approximation. The interaction between electrons is studied in the mean-held Hubbard model. Our results indicate that both phonon-restricted and phonon-assisted transport through two different configurations of graphene quantum dot occur. Also, the electron-phonon interaction screens the electron-electron interaction, and reduces the spin polarization. (C) 2014 Elsevier B.V. All rights reserved.