title: A single molecule rectifier with strong push-pull coupling.
abstract: We theoretically investigate the electronic charge transport in a molecular system composed of a donor group (dinitrobenzene) coupled to an acceptor group (dihydrophenazine) via a polyenic chain (unsaturated carbon bridge). Ab initio calculations based on the Hartree-Fock approximations are performed to investigate the distribution of electron states over the molecule in the presence of an external electric field. For small bridge lengths (n=0-3) we find a homogeneous distribution of the frontier molecular orbitals, while for n>3 a strong localization of the lowest unoccupied molecular orbital is found. The localized orbitals in between the donor and acceptor groups act as conduction channels when an external electric field is applied. We also calculate the rectification behavior of this system by evaluating the charge accumulated in the donor and acceptor groups as a function of the external electric field. Finally, we propose a phenomenological model based on nonequilibrium Green's function to rationalize the ab initio findings.
authors.affiliation: Departamento de Física, Universidade Federal do Ceará, Ceará, Brazil.
authors.forename: Aldilene
authors.initials: A
authors.lastname: Saraiva-Souza
authors.forename: Fabricio
authors.initials: F
authors.lastname: Macedo de Souza
authors.forename: Vicente F P
authors.initials: VF
authors.lastname: Aleixo
authors.forename: Eduardo Costa
authors.initials: EC
authors.lastname: Girão
authors.forename: Josué Mendes
authors.initials: JM
authors.lastname: Filho
authors.forename: Vincent
authors.initials: V
authors.lastname: Meunier
authors.forename: Bobby G
authors.initials: BG
authors.lastname: Sumpter
authors.forename: Antonio Gomes
authors.initials: AG
authors.lastname: Souza Filho
authors.forename: Jordan
authors.initials: J
authors.lastname: Del Nero