Asymmetric line shape and Fano interference in the transport of electrons through a multilevel quantum dot in the Coulomb blockade regime

We investigate the resonant transmission of electrons through a multilevel quantum in the Coulomb blockade regime. We show that the quantum interference between the path through the resonant level and the paths via other (nonresonant) levels results in the Fano asymmetry of the transmission peaks. The Fano parameter q is expressed in terms of the level spacing and the dot-lead coupling. The Coulomb blockade provides another origin of asymmetry for the resonances of the conductance due to the asymmetric occupation about a resonant point. Physical ingredients that influence these two mechanisms of the asymmetry are discussed.