RKKY interaction in the nearly-nested Fermi liquid

TL;DR

This paper analytically evaluates the RKKY interaction in layered metals with nearly nested Fermi surfaces, revealing oscillatory behaviors and sign-reversal antiferromagnetic interactions with closed-form expressions.

Contribution

It provides new analytical formulas for the RKKY interaction in nearly nested Fermi liquids, extending previous results to intermediate distances and confirming them with numerical data.

Findings

Identification of the 2k_F oscillations as the far asymptote.

Existence of an intermediate asymptote with sign-reversal antiferromagnetic interaction.

Good agreement between analytical formulas and numerical calculations.

Abstract

We present the results of analytical evaluation of the indirect RKKY interaction in a layered metal with nearly nested (almost squared) Fermi surface. The final expressions are obtained in closed form as a combination of Bessel functions. We discuss the notion of the ``2k_F'' oscillations and show that they occur as the far asymptote of our expressions. We show the existence of the intermediate asymptote of the interaction which is of the sign-reversal antiferromagnetic type and is the only term surviving in the limit of exact nesting. A good accordance of our analytical formulas with numerical findings is demonstrated until the interatomic distances. The obtained expressions for the Green's functions extend the previous analytical results into the region of intermediate distances as well.