Correlation Length of the S=2 Antiferromagnetic Heisenberg Chain

Abstract

Temperature dependence of the correlation length of the one-dimensional S=2 Heisenberg antiferromagnet is investigated numerically, to compare with those of the S=1⁄2, 1, 3/2 models. The correlation length of the S=2 model is found to be saturated to a value ξ⁻¹\simeq0.012(2) as T→0, which confirms the Haldane conjecture. Combined with the estimate ξ⁻¹\simeq0.16 of the S=1 model by other authors, the present estimate is well explained by ξ⁻¹∼S exp (−πS).