Transport through an interacting quantum dot driven out-of-equilibrium

Abstract

We study a single-level quantum dot in the presence of strong Coulomb interaction under nonequilibrium condition. By extending the equation of motion method to nonequilibrium, we study the transport behavior of the system when a dc bias voltage is applied to the leads. The spectral density exhibits two broad peaks centered around the normalized dot level energies and a split Kondo resonance at low temperature with two peaks pinned at the Fermi level of each lead. The approach allows one to recover the unitary condition for the density of states at the Fermi levels and by the way to cure the long-standing problem about the presence of spurious peak in the density of states at equilibrium. Finally we discuss the consequences for the linear and differential conductances of the quantum dot in its steady state.