Journal of Physics Condensed Matter
The thermodynamics of the anisotropic spin-SXXZ chain in the high-temperature region
Onofre Rojas, S. M. de Souza, E V Corrêa Silva, M. T. Thomaz
Abstract
We report analytical calculations of the Helmholtz free energy of non-integrable anisotropic quantum XXZ chains in the high-temperature regime for several values of the spin S . Single-ion anisotropy and interaction with an external magnetic field are taken into account. The seven lowest-order terms in the high-temperature expansion of Helmholtz free energy are obtained. Our results contribute to the existing literature on high-temperature expansions and numerical studies of those models by discussing the effects of anisotropy upon their high-temperature thermodynamic properties, such as the average energy per site, the specific heat and magnetic susceptibility.