Neutron scattering experiments have been performed on Sr14Cu24O41 which consists of both chains and ladders of copper ions. We observed that the magnetic excitations from the CuO2 chain have two branches and that both branches are weakly dispersive along the a and c axes. The ω-Q dispersion relation as well as the intensities can be reasonably described by a random phase approximation with intradimer coupling between next-nearest-neighbor copper spins J=11 meV, interdimer coupling along the c axis Jc=0.75 meV, and interdimer coupling along the a axis Ja=0.75 meV. The dimer configuration indicates a quasi-two-dimensional hole ordering, resulting in an ordering of magnetic Cu2+ with spin-1/2 and nonmagnetic Cu, which forms the Zhang-Rice singlet. We have also studied the effect of Ca substitution for Sr on the dimer and the hole ordering.
@article{arxiv.cond-mat/9808083,
title = {Quasi-two-dimensional hole ordering and dimerized state in the CuO2-chain layers in Sr14Cu24O41},
author = {M. Matsuda and T. Yoshihama and K. Kakurai and G. Shirane},
journal= {arXiv preprint arXiv:cond-mat/9808083},
year = {2009}
}
Comments
7 pages, Revtex, 10 figures, Submitted to Phys. Rev. B