Evolution of the multiband RKKY interaction: Application to iron pnictides and chalcogenides

TL;DR

This paper analyzes the multiband RKKY interaction in iron-based superconductors, revealing multiple oscillation length scales and their implications for magnetic order, using simplified and realistic Fermi surface models.

Contribution

It introduces a detailed analysis of the multiband RKKY interaction in iron pnictides and chalcogenides, highlighting the effects of multi-band features on magnetic oscillations and order.

Findings

Multiple length scales of RKKY oscillations identified

Momentum dependence of RKKY interaction analyzed in different phases

Insights into magnetic ordering in iron-based superconductors provided

Abstract

The indirect RKKY interaction in iron pnictide and chalcogenide metals is calculated for a simplified four bands Fermi surface (FS) model. We investigate the specific multi-band features and show that distinct length scales of the RKKY oscillations appear. For the regular lattice of the local moments, the generalized RKKY interaction is defined in momentum space. We consider its momentum dependence in paramagnetic and spin density wave (SDW) phases, discuss its implications for the possible type of magnetic order and compare it to the results obtained from more realistic tight-binding type Fermi surface model. Our finding can give important clues on the magnetic ordering of the 4f- iron based superconductors.