Triplet Dispersion in CuGeO_3: Perturbative Analysis
Abstract
We reconsider the 2d model for CuGeO_3 introduced previously (Phys. Rev. Lett. 79, 163 (1997)). Using a computer aided perturbation method based on flow equations we expand the 1-triplet dispersion up to 10th order. The expansion is provided as a polynom in the model parameters. The latter are fixed by fitting the theoretical result to experimental data obtained by INS. For a dimerization delta = 0.08(1) we find an excellent agreement with experiment. This value is at least 2 to 3 times higher than values deduced previously from 1d chain approaches. For the intrachain frustration alpha_0 we find a smaller value of 0.25(3). The existence of interchain frustration conjectured previously is confirmed by the analysis of temperature dependent susceptibility.
Keywords
Cite
@article{arxiv.cond-mat/0004243,
title = {Triplet Dispersion in CuGeO_3: Perturbative Analysis},
author = {Christian Knetter and Goetz S. Uhrig},
journal= {arXiv preprint arXiv:cond-mat/0004243},
year = {2009}
}
Comments
8 pages, 10 figures, submitted to Phys. Rev. B