Impurity-Induced Antiferromagnetic Domains in the Periodic Anderson Model

TL;DR

This paper investigates how impurities with local hybridization below the critical value induce antiferromagnetic domains within a singlet phase of the Periodic Anderson Model, using Quantum Monte Carlo simulations.

Contribution

It provides the first detailed simulation study of impurity-induced antiferromagnetic domains in the PAM, aligning with experimental NMR results in CeCoIn$_{5-x}$Cd$_x$.

Findings

Impurities with local hybridization below the critical value induce antiferromagnetic domains.

The size of the antiferromagnetic domains depends on impurity concentration and hybridization.

Results qualitatively agree with NMR measurements in CeCoIn$_{5-x}$Cd$_x$.

Abstract

A central feature of the Periodic Anderson Model is the competition between antiferromagnetism, mediated by the Ruderman-Kittel-Kasuya-Yosida interaction at small conduction electron-local electron hybridization $V$, and singlet formation at large $V$. At zero temperature, and in dimension $d>1$, these two phases are separated by a quantum critical point $V_c$. We use Quantum Monte Carlo simulations to explore the effect of impurities which have a local hybridization $V_{*} < V_c$ in the AF regime which are embedded in a bulk singlet phase with $V > V_c$. We measure the suppression of singlet correlations and the antiferromagnetic correlations which form around the impurity, as well as the size of the resulting domain. Our calculations agree qualitatively with NMR measurements in CeCoIn$_{5-x}$Cd$_x$.