Abstract
The dynamical properties of spin-1 and spin-1/2 antiferromagnetic Heisenberg chains (AHC’s) are studied by diagonalizing exactly clusters of up to 18 and 26 sites, respectively. It is shown that the spin-1 AHC has a quasi-single-mode spectrum for momentum k≥0.3π, while the low-energy edge of the spin-1/2 AHC is dominated by a spin-wave continuum. The dispersion curve obtained for the spin-1 chain is in excellent agreement with recent experiments on Ni(. The size dependence of the low-energy spectral weights is also analyzed.
- Received 22 January 1993
DOI:https://doi.org/10.1103/PhysRevB.48.3281
©1993 American Physical Society