The RKKY interactions and the Mott Transition

TL;DR

This paper investigates how RKKY interactions influence the Mott transition in a two-site Hubbard model, revealing that short-range spin correlations can qualitatively alter the metal-insulator transition without long-range magnetic order.

Contribution

It introduces a two-site cluster model mapped to a two-impurity Kondo-Anderson system to study the impact of RKKY interactions on the Mott transition.

Findings

RKKY interactions cause qualitative changes in the MIT scenario.

Short-range spin correlations significantly affect the transition.

Long-range antiferromagnetic order is not necessary for these effects.

Abstract

A two-site cluster generalization of the Hubbard model in large dimensions is examined in order to study the role of short-range spin correlations near the metal-insulator transition (MIT). The model is mapped to a two-impurity Kondo-Anderson model in a self-consistently determined bath, making it possible to directly address the competition between the Kondo effect and RKKY interactions in a lattice context. Our results indicate that the RKKY interactions lead to qualitative modifications of the MIT scenario even in the absence of long range antiferromagnetic ordering.