Document Type
Article
Date of Original Version
1-1-1994
Abstract
The spectral densities of dynamical spin autocorrelation functions at infinite temperature are studied for the S = 1/2 XXZ model (with exchange couplings Jx = Jy = J,Jz) on the linear chain, the square lattice, and the simple cubic lattice. The low-frequency behavior of a given spectral density is inferred from certain characteristic properties of its continued-fraction coefficients as determined from computed frequency moments. The analysis yields estimates for the Jz/J dependence of the infrared-singularity exponent. In the d = 1 case, the exponent for spin fluctuations perpendicular to the O(2) symmetry axis responds sensitively as the anisotropy parameter sweeps across the O(3) symmetry point Jz/J = 1, while the exponent for the parallel fluctuations shows little variation. In the cases d = 2 and d = 3 the same observations are made for autocorrelation functions of aggregate spins in chains and lattice planes, respectively.
Citation/Publisher Attribution
Markus Böhm, Hajo Leschke, Martin Henneke, V.S. Viswanath, Joachim Stolze and Gerhard Müller. Spectral signature of quantum spin diffusion in dimensions d=1,2,3. Phys. Rev. B 49 (1994), 417-421.
Available at: http://journals.aps.org/prb/abstract/10.1103/PhysRevB.49.417
Terms of Use
All rights reserved under copyright.
Publisher Statement
Copyright 1994 The American Physical Society.