Anisotropic charge Kondo effect in a triple quantum dot

TL;DR

This paper predicts an anisotropic charge Kondo effect in a triple quantum dot system with two degenerate charge states, revealing phase transitions that can be experimentally observed via conductance measurements.

Contribution

It introduces the concept of anisotropic charge Kondo effect in a triple quantum dot and analyzes its phases using bosonization and refermionization methods.

Findings

Identification of two distinct phases: charge fluctuation and vanishing fluctuation.

Phase transition observable through electron conductance.

Similarity of the effect to negative-U Anderson impurity.

Abstract

We predict that an anisotropic charge Kondo effect appears in a triple quantum dot, when the system has two-fold degenerate ground states of (1,1,0) and (0,0,1) charge configurations. Using bosonization and refermionization methods, we find that at low temperature, the system has the two different phases of massive charge fluctuations between the two charge configurations and vanishing fluctuations, which are equivalent with the Kondo-screened and ferromagnetic phases of the anisotropic Kondo model, respectively. The phase transition is identifiable by electron conductance measurement, offering the possibility of experimentally exploring the anisotropic Kondo model. Our charge Kondo effect has similar origin to that in a negative-U Anderson impurity.