Oscillation and suppression of Kondo temperature by RKKY coupling in two-site Kondo systems

TL;DR

This paper uses a self-consistent RG method to analyze STM spectra of a two-impurity Kondo system, revealing how RKKY interactions cause oscillations and suppression of the Kondo temperature based on chain length.

Contribution

The study introduces a self-consistent RG approach to describe local spin screening in multi-impurity Kondo systems with RKKY interaction, explaining experimental observations.

Findings

RKKY interaction causes oscillations in Kondo temperature.

Kondo temperature suppression is explained by RKKY coupling.

Results are consistent for both ferromagnetic and antiferromagnetic RKKY interactions.

Abstract

We apply our recently developed, selfconsistent renormalization group (RG) method to STM spectra of a two-impurity Kondo system consisting of two cobalt atoms connected by a one-dimensional Cu chain on a Cu surface. This RG method was developed to describe local spin screening in multi-impurity Kondo systems in presence of the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction. Using the RKKY interaction of a one-dimensional chain, we explain the experimentally observed suppression and oscillation of the Kondo temperature, $T_K(y)$, as a function of the length of the chain and the corresponding RKKY interaction parameter $y$, regardless of the RKKY coupling being ferromagnetic or antiferromagnetic.