Impurities near an Antiferromagnetic-Singlet Quantum Critical Point

Abstract

Heavy fermion systems, and other strongly correlated electron materials, often exhibit a competition between antiferromagnetic (AF) and singlet ground states. Using exact Quantum Monte Carlo (QMC) simulations, we examine the effect of impurities in the vicinity of such AF- singlet quantum critical points, through an appropriately defined impurity susceptibility, ${\chi }_{imp}$. Our key finding is a connection, within a single calculational framework, between AF domains induced on the singlet side of the transition, and the behavior of the nuclear magnetic resonance (NMR) relaxation rate $1/T_1$. We show that local NMR measurements provide a diagnostic for the location of the QCP which agrees remarkably well with the vanishing of the AF order parameter and large values of ${\chi }_{imp}$. We connect our results with experiments on Cd-doped CeCoIn${}_5$.

References in corpus (7)

• Reversible Tuning of the Heavy Fermion Ground State in CeCoIn${}_5$
• Interacting Antiferromagnetic Droplets in Quantum Critical CeCoIn_5
• Disorder-Induced Static Antiferromagnetism in Cuprate Superconductors
• Disorder in a Quantum Critical Superconductor
• Long range order and two-fluid behavior in heavy electron materials
• Impurity induced spin texture in quantum critical 2D antiferromagnets
• Universal Knight shift anomaly in the Periodic Anderson model

Cited by in corpus (1)

• Tunable magnetism of a hexagonal Anderson droplet on the triangular lattice