Crossover from conventional to inverse indirect magnetic exchange in the depleted Anderson lattice

TL;DR

This paper explores how magnetic exchange mechanisms in a depleted Anderson lattice transition from RKKY to inverse indirect exchange as hybridization strength increases, affecting ferromagnetic stability and Curie temperature.

Contribution

It identifies and characterizes a crossover between RKKY and inverse indirect magnetic exchange mechanisms in a depleted Anderson lattice.

Findings

Maximum Curie temperature at half-filling and intermediate hybridization

Ferromagnetic order stable against thermal fluctuations

Distinct regimes dominated by RKKY and IIME mechanisms

Abstract

We investigate the finite-temperature properties of an Anderson lattice with regularly depleted impurities. The physics of this model is ruled by two different magnetic exchange mechanisms: conventional Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction at weak hybridization strength V and a novel inverse indirect magnetic exchange (IIME) at strong V, both favoring a ferromagnetic ground state. The stability of ferromagnetic order against thermal fluctuations is systematically studied by static mean-field theory for an effective low-energy spin-only model emerging perturbatively in the strong-coupling limit as well as by dynamical mean-field theory for the full model. The Curie temperature is found at a maximum for a half-filled conduction band and at intermediate hybridization strengths in the crossover regime between RKKY and IIME.