Temperature Dependence of the Correlation Length of in Spin-1/2 Alternating Heisenberg-XY Antiferromagnets

清美 岡本, Kiyomi Okamoto

Antonio S. T. Pires

清美 岡本, Kiyomi Okamoto

, Correlation Function <Siz Sjz> in Spin--1/2 Alternating Heisenberg-XY Antiferromagnets in One-Dimension in Spin-1/2 Alternating Heisenberg-XY Antiferromagnets in One-Dimension

B.B Beard

Anatoli G. Izergin, V. E. Korepin, N. A. Slavnov

Kiyomi Okamoto

We conjecture the temperature dependence of the correlation length ξ of the spin-spin correlation function < S i z S j z > in spin-1/2 alternating Heisenberg- X Y antifer-romagnets. We use the phase representation and the self-consistent harmonic approx-imation to evaluate < S i z S j z >. The correlation length ξ as a furtction of the temperaturehas a peak at T ∼ ε g , where ε g is the energy gap between the ground state and the first excited state.