Transport spectroscopy of Kondo quantum dots coupled by RKKY interaction

TL;DR

This paper develops a theoretical framework for understanding the conductance behavior of coupled quantum dots with RKKY interaction, enabling identification of ground states and transitions through conductance measurements.

Contribution

It introduces a new theoretical model for the conductance of RKKY-coupled quantum dots, linking conductance features to ground state transitions and experimental observables.

Findings

Dependence of differential conductance on bias and magnetic field reveals ground state characteristics.

Tuning RKKY interaction induces transitions between different ground states.

Temperature dependence of linear conductance provides insights into the nature of these transitions.

Abstract

We develop the theory of conductance of a quantum dot which carries a spin and is coupled via RKKY interaction to another spin-carrying quantum dot. The found dependence of the differential conductance on bias and magnetic field at fixed RKKY interaction strength may allow one to distinguish between the possible ground states of the system. Transitions between the ground states are achieved by tuning the RKKY interaction, and the nature of these transitions can be extracted from the temperature dependence of the linear conductance. The feasibility of the corresponding measurements is evidenced by recent experiments by Craig et al. [cond-mat/0404213].