Numerical study of finite size effects in the one-dimensional two-impurity Anderson model

TL;DR

This study numerically investigates finite size effects in the one-dimensional two-impurity Anderson model, revealing how magnetic correlations and transport properties depend on impurity coupling, boundary conditions, and Coulomb interactions, with implications for quantum dot devices.

Contribution

It provides a detailed numerical analysis of finite size effects and the interplay between Kondo and RKKY interactions in the two-impurity Anderson model.

Findings

Magnetic correlations deviate from pure 2k_F oscillations due to boundary effects.

Different behaviors in spin correlations and transport are linked to the dominance of Kondo or RKKY interactions.

Increasing Coulomb repulsion restores 2k_F periodicity when RKKY dominates.

Abstract

We study the two-impurity Anderson model on finite chains using numerical techniques. We discuss the departure of magnetic correlations as a function of the interimpurity distance from a pure 2k_F oscillation due to open boundary conditions. We observe qualitatively different behaviors in the interimpurity spin correlations and in transport properties at different values of the impurity couplings. We relate these different behaviors to a change in the relative dominance between the Kondo effect and the Ruderman-Kittel-Kasuya-Yoshida (RKKY) interaction. We also observe that when RKKY dominates there is a definite relation between interimpurity magnetic correlations and transport properties. In this case, there is a recovery of 2k_F periodicity when the on-site Coulomb repulsion on the chain is increased at quarter-filling. The present results could be relevant for electronic nanodevices implementing a non-local control between two quantum dots that could be located at variable distance along a wire.