Dilution-controlled quantum criticality in rare-earth nickelates.
A microscopic model for the diluted spin-mixed compounds (RxY1-x)2BaNiO5 (R=magnetic rare earth) is studied using quantum Monte Carlo simulations. The ordering temperature is shown to be a universal function of the impurity concentration x and the intrinsic Ni-chain correlation length. An effective model for the critical modes is derived. The possibility of a quantum critical point driven by the rare-earth concentration and the existence of a quantum Griffiths phase in the high dilution limit is investigated. Several possible experimental approaches to verify the results are put forward.
Alvarez
J V
JV
Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA.
Rieger
H
H
Zheludev
A
A