Finite temperature properties of the two-dimensional SU(2) Kondo-necklace

TL;DR

This paper investigates the finite-temperature thermodynamic properties of the two-dimensional SU(2) Kondo-necklace model, identifying a quantum critical point and analyzing various susceptibilities and structure factors across different regimes.

Contribution

It provides the first finite-temperature analysis of the 2D SU(2) Kondo-necklace, confirming the quantum critical point and characterizing crossover regimes.

Findings

Existence of a quantum critical point at J_c ≈ 1.4

Temperature-dependent structure factors and susceptibilities characterized

Crossover between classical, renormalized classical, and quantum critical regimes

Abstract

We analyse several thermodynamic properties of the two-dimensional Kondo necklace using finite-temperature stochastic series expansion. In agreement with previous zero-temperature findings the model is shown to exhibit a quantum critical point (QCP), separating an antiferromagnetic from a paramagnetic dimerized state at a critical Kondo exchange-coupling strength $J_{c}\approx 1.4$. We evaluate the temperature dependent uniform and staggered structure factors as well as the uniform and staggered susceptibilities and the local 'impurity' susceptibility close to the QCP as well as in the ordered and quantum disordered phase. The crossover between the classical, renormalized classical, and quantum critical regime is analyzed as a function of temperature and Kondo coupling.