MAGNETISM IN THE DISORDERED TWO-DIMENSIONAL KONDO-NECKLACE

Abstract

We analyze the effects of site-dilution disorder on the thermodynamic properties of the two-dimensional Kondo necklace using finite-temperature stochastic series expansion. Results will be discussed for the dependence on dilution concentration, temperature, and Kondo exchange-coupling strength of the uniform susceptibility, the staggered structure factor, and the Chakravarty-Halperin-Nelson ratio. Dilution is shown to induce effective free-spin clusters in the gapped phase of the clean system with a low-temperature Curie constant renormalized below 1/4. Furthermore, dilution is demonstrated to suppress the quantum critical point of the clean system and to generate antiferromagnetic order in the quantum disordered phase of the clean system, i.e. order-from-disorder.