Transport model of controlled molecular rectifier showing unusual negative differential resistance effect.
We investigate theoretically the charge accumulated Q in a three-terminal molecular device in the presence of an external electric field. Our approach is based on ab initio Hartree-Fock and density functional theory methodology contained in Gaussian package. Our main finding is a negative differential resistance (NDR) in the charge Q as a function of an external electric field. To explain this NDR effect we apply a phenomenological capacitive model based on a quite general system composed of many localized levels (that can be LUMOs of a molecule) coupled to source and drain. The capacitance accounts for charging effects that can result in Coulomb blockade (CB) in the transport. We show that this CB effect gives rise to a NDR for a suitable set of phenomenological parameters, like tunneling rates and charging energies. The NDR profile obtained in both ab initio and phenomenological methodologies are in close agreement.
Pós-graduação em Engenharia Elétrica, Universidade Federal do Pará, 66075-900, Belém-PA, Brazil.
Ewerton Ramos
ER
Granhen
Marcos Allan Leite
MA
Reis
Fabrício M
FM
Souza
Jordan
J
Del Nero