Nonequilibrium conductance of a three-terminal quantum dot in the Kondo regime: Perturbative renormalization group study

Abstract

Motivated by recent experiments, we consider a single-electron transistor in the Kondo regime which is coupled to three leads in the presence of large bias voltages. Such a steady-state nonequilibrium system is to a large extent governed by a decoherence rate $\ensuremath{\Gamma}$ induced by the current through the dot. As the two-terminal conductance turns out to be rather insensitive to $\ensuremath{\Gamma}$, we study the conductance in a three-terminal device using a perturbative renormalization group method and calculate the characteristic splitting of the Kondo resonance. The interplay between potential biases and anisotropy in coupling to the three leads determines $\ensuremath{\Gamma}$ and the conditions for strong coupling.