Chinese Physics Letters
Specific Heat of the Spin-1/2 Antiferromagnetic Heisenberg Chain
Guohong Yun, Liang Xi-Xia
Abstract
A simple analytic theory of thermodynamics at finite temperature for the spin-1/2 antiferromagnetic Heisenberg chain is proposed based on the picture of the particle-hole pair excitations. The dispersion relation of the particle-hole pairs is derived in the formulation of thermodynamic Bethe ansatz provided that the particles and holes have the same energy and they are excited as normal modes. It is shown that the behaviour of the specific heat is in excellent agreement with the numerical and experimental results.