Universal Knight shift anomaly in the Periodic Anderson model
  We report a Determinant Quantum Monte Carlo investigation which quantifies the behavior of the susceptibility and the entropy in the framework of the periodic Anderson model (PAM), focussing on the evolution with different degree of conduction electron (c) -local moment (f) hybridization. These results capture the behavior observed in several experiments, including the universal behavior of the NMR Knight shift anomaly below the crossover temperature, $T^{\ast}$. We find that $T^{\ast}$ is a measure of the onset of c-f correlations and grows with increasing hybridization. These results suggest that the NMR Knight shift and spin-lattice relaxation rate measurements in non-Fermi liquid materials are strongly influenced by temperature-dependent hybridization processes. Our results provide a microscopic basis for the phenomenological two-fluid model of Kondo lattice behavior, and its evolution with pressure and temperature. 
Mi Jiang, Nicholas J. Curro, Richard T. Scalettar
cond-mat.str-el