Critical Properties ofS=1/2 XXZ Chain

The S x S x correlation function of S =1/2 XXZ chain is numericaly obtained at low temperatures by means of the transfer matrix with use of the Trotter approximation. The inplane susceptibility and the correlation length are extrapolated to N =∞ where N is the number of the Trotter slicings. It is shown that the extrapolation works quite effectively and makes the estimation of the critical indices ν, γ and η possible for the anisotropy parameter -0.75≤Δ≤0.5. The obtained values of ν, γ and η satisfy the scaling relation and agree quite well with the analytic expression derived by Luther and Peschel.