Quantum lattice fluctuations in a frustrated Heisenberg spin-Peierls chain
Abstract
As a simple model for spin-Peierls systems we study a frustrated Heisenberg chain coupled to optical phonons. In view of the anorganic spin-Peierls compound CuGeO3 we consider two different mechanisms of spin-phonon coupling. Combining variational concepts in the adiabatic regime and perturbation theory in the anti-adiabatic regime we derive effective spin Hamiltonians which cover the dynamical effect of phonons in an approximate way. Ground-state phase diagrams of these models are determined, and the effect of frustration is discussed. Comparing the properties of the ground state and of low-lying excitations with exact diagonalization data for the full quantum spin phonon models, good agreement is found especially in the anti-adiabatic regime.
Cite
@article{arxiv.cond-mat/9901262,
title = {Quantum lattice fluctuations in a frustrated Heisenberg spin-Peierls chain},
author = {A. Weisse and G. Wellein and H. Fehske},
journal= {arXiv preprint arXiv:cond-mat/9901262},
year = {2007}
}
Comments
9 pages, 7 figures included, submitted to Phys. Rev. B