title: Unifying magnons and triplons in stripe-ordered cuprate superconductors.
abstract: 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 La15/8Ba1/8CuO4, 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 Jcyc/J=0.2-0.25.
authors.affiliation: Institut für Theoretische Physik, Universität zu Köln, Zülpicher Strasse 77, D-50937 Köln, Germany.
authors.forename: G S
authors.initials: GS
authors.lastname: Uhrig
authors.forename: K P
authors.initials: KP
authors.lastname: Schmidt
authors.forename: M
authors.initials: M
authors.lastname: Grüninger