Competition Between Antiferromagnetic Order and Spin-Liquid Behavior in the Two-Dimensional Periodic Anderson Model at Half-Filling

TL;DR

This paper investigates the two-dimensional periodic Anderson model at half-filling, revealing a transition between magnetic order and disorder, and explores the competition between Kondo effect and antiferromagnetic order using quantum Monte Carlo methods.

Contribution

It provides new insights into the phase transition and excitation spectrum of the model, highlighting the interplay between magnetic order and Kondo screening.

Findings

Ground state exhibits a magnetic order-disorder transition.

Finite temperature shows competition between Kondo effect and antiferromagnetic order.

Spin and charge excitations characterized using maximum entropy method.

Abstract

We study the two-dimensional periodic Anderson model at half-filling using quantum Monte Carlo (QMC) techniques. The ground state undergoes a magnetic order-disorder transition as a function of the effective exchange coupling between the conduction and localized bands. Low-lying spin and charge excitations are determined using the maximum entropy method to analytically continue the QMC data. At finite temperature we find a competition between the Kondo effect and antiferromagnetic order which develops in the localized band through Ruderman-Kittel-Kasuya-Yosida interactions.