Evidence for site-centered stripes from magnetic excitations in cuprate superconductors

The success of models of coupled two-leg spin ladders in describing the magnetic excitation spectrum of La(2-x)Ba(x)CuO(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 stripe modeled by two-or three-leg ladder, 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.