Transport Through a Quantum Dot with Coulombic Dot-Lead Coupling

Abstract

We investigate joint effects of the Coulombic dot-lead interaction and intralead electron interaction on current through a quantum dot weakly coupled to Luttinger liquid leads. A general formula of current is derived by applying the canonical transformation and the nonequilibrium Green function technique. At low temperature and weak intralead interaction, the current exhibits staircase behavior with the Coulombic dot-lead interaction. When temperature or the intralead interaction increases, the steps are rounded. For a weak or moderately strong interaction the differential conductance as a function of bias voltage demonstrates resonant behavior. The dot-lead exchange scattering processes can dominate electron transport for a certain region of interaction strength. This result implies the possibility of controlling the differential conductance of the transistor by tuning the Coulombic dot-lead coupling.