Spin-Peierls transition in the Heisenberg chain with finite-frequency phonons
Strongly Correlated Electrons
2009-10-31 v1
Abstract
We study the spin-Peierls transition in a Heisenberg spin chain coupled to optical bond-phonons. Quantum Monte Carlo results for systems with up to N=256 spins show unambiguously that the transition occurs only when the spin-phonon coupling alpha exceeds a critical value alpha_c. Using sum rules, we show that the phonon spectral function has divergent (for infinite N) weight extending to zero frequency for alpha < alpha_c. The equal-time phonon-phonon correlations decay with distance r as 1/r. This behavior is characteristic for all 0 < alpha < alpha_c and the q=pi phonon does not soften (to zero frequency) at the transition.
Cite
@article{arxiv.cond-mat/9902230,
title = {Spin-Peierls transition in the Heisenberg chain with finite-frequency phonons},
author = {Anders W. Sandvik and David K. Campbell},
journal= {arXiv preprint arXiv:cond-mat/9902230},
year = {2009}
}
Comments
5 pages, 4 figures