Planar and local anisotropies in the Kondo necklace model

Abstract

Using the density matrix renormalization group method, we study the one-dimensional Kondo necklace model including two anisotropies: h in the XY interaction of the conduction chain, and D in the local Kondo coupling between localized and conduction spins. For different values of the anisotropies, we calculate the energy gap and estimate the quantum critical points in which a phase transition from antiferromagnetic to spin liquid states takes place, assuming a Kosterlitz-Thoulesslike behavior. For the case h ¼ 0, the system remains in a spin liquid state for the different D considered, but when h 6 ¼ 0, D markedly affects the location of the critical points. We also calculate correlation functions for a specific case, in order to support our gap results.