Thermoelectrics of a two-channel charge Kondo circuit: Role of electron-electron interactions in a quantum point contact

Abstract

In this Letter we investigate properties of a quantum impurity model in the presence of additional many-body interactions between mobile carriers. The fundamental question which is addressed here is how the interactions in charge and spin sectors of itinerant system affect the quantum impurity physics in the vicinity of the intermediate coupling fixed point. To illustrate the general answer to this question we discuss a two channel charge Kondo circuit model. We show that the electronelectron interactions resulting in formation of a massive spin mode in the itinerant electrons sub-set drive the system away from the unstable Non-Fermi liquid (NFL) fixed point to the stable Fermi liquid (FL) regime. We discuss thermoelectric response as a benchmark for the NFL-FL crossover.