The success of models of coupled two-leg spin ladders in describing the magnetic excitation spectrum of La_[2-x]Ba_xCuO_4 has been widely interpreted as evidence for bond-centered stripes. Here, we determine the magnetic coupling induced by the charge stripes between bond- or site-centered spin stripes modeled by two- or three-leg ladders, respectively. We find that only the site-centered models order. We further report excellent agreement of a fully consistent analysis of coupled three-leg ladders using a spin wave theory of bond operators with the experiment.
@article{arxiv.1009.3122,
title = {Evidence for site-centered stripes from magnetic excitations in CuO superconductors},
author = {Martin Greiter and Holger Schmidt},
journal= {arXiv preprint arXiv:1009.3122},
year = {2010}
}