Magnetic Susceptibility of an integrable anisotropic spin ladder system

TL;DR

This paper analyzes an exactly solvable anisotropic spin ladder model, revealing a phase transition and accurately matching experimental magnetic susceptibility data for related compounds.

Contribution

It introduces a new integrable spin ladder model with an additional parameter and provides exact solutions that connect theoretical predictions with experimental results.

Findings

Identifies a phase transition between gapped and gapless spectra.

Provides numerical magnetic susceptibility curves matching experiments.

Establishes a link between the model and real compound behaviors.

Abstract

We investigate the thermodynamics of a spin ladder model which possesses a free parameter besides the rung and leg couplings. The model is exactly solved by the Bethe Ansatz and exhibits a phase transition between a gapped and a gapless spin excitation spectrum. The magnetic susceptibility is obtained numerically and its dependence on the anisotropy parameter is determined. A connection with the compounds KCuCl3, Cu2(C5H12N2)2Cl4 and (C5H12N)2CuBr4 in the strong coupling regime is made and our results for the magnetic susceptibility fit the experimental data remarkably well.