physica status solidi (b)
Thermodynamic properties of a spin‐1 antiferromagnetic chain with an anisotropy at a finite temperature
Jialiang Li, Suhua Zhu
Abstract
Abstract In this paper a self‐consistent mean‐field approximation is used to study the thermodynamic properties of a spin‐1 antiferromagnetic Heisenberg chain with an anisotropy in the presence of an external magnetic field at a finite temperature. The temperature dependences of the internal energy, Haldane gap, and correlation length are presented. It is found that the internal energy and Haldane gap increase with increasing temperature, while the correlation length decreases for a fixed magnetic field and single‐ion anisotropy. The magnetic field splits the Haldane gap into two branches: the upper branch increases with increasing magnetic field while the other branch decreases. The numerical results are consistent with those of other theoretical methods. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)