Spin Correlation Functions in Randomexchange s=1/2 XXZ Chains

Authors

Heinrich Röder
Joachim Stolze
Richard N. Silver
Gerhard Müller, University of Rhode IslandFollow

Document Type

Article

Date of Original Version

4-15-1996

Abstract

The decay of (disorder‐averaged) static spin correlation functions at T=0 for the one‐dimensional spin‐1/2 XXZantiferromagnet with uniform longitudinal coupling JΔ and random transverse coupling Jλ _i is investigated by numerical calculations for ensembles of finite chains. At Δ=0 (XXmodel) the calculation is based on the Jordan‐Wigner mapping to free lattice fermions for chains with up to N=100 sites. At Δ≠0 Lanczos diagonalizations are carried out for chains with up to N=22 sites. The longitudinal correlation function 〈S ^z ₀ S ^z _r 〉 is found to exhibit a power‐law decay with an exponent that varies with Δ and, for nonzero Δ, also with the width of the λ _i ‐distribution. The results for the transverse correlation function 〈S ^x ₀ S ^x _r 〉 show a crossover from power‐law decay to exponential decay as the exchange disorder is turned on.

Citation/Publisher Attribution

Heinrich Röder, Joachim Stolze, Richard N. Silver and Gerhard Müller. Spin correlation functions in random-exchange s=1/2 XXZ chains. J. Appl. Phys. 79 (1996), 4632-4634.

Available at http://dx.doi.org/10.1063/1.361687.