Based on a two-dimensional model of coupled two-leg spin ladders, we derive a unified picture of recent neutron scattering data of stripe-ordered La_(15/8)Ba_(1/8)CuO_4, namely of the low-energy magnons around the superstructure satellites and of the triplon excitations at higher energies. The resonance peak at the antiferromagnetic wave vector Q_AF in the stripe-ordered phase corresponds to a saddle point in the dispersion of the magnetic excitations. Quantitative agreement with the neutron data is obtained for J= 130-160 meV and J_cyc/J = 0.2-0.25.
@article{arxiv.cond-mat/0402659,
title = {Unifying Magnons and Triplons in Stripe-Ordered Cuprate Superconductors},
author = {G. S. Uhrig and K. P. Schmidt and M. Grüninger},
journal= {arXiv preprint arXiv:cond-mat/0402659},
year = {2009}
}
Comments
4 pages, 4 figures included updated version taking new data into account; factor in spectral weight corrected; Figs. 2 and 4 changed