Phonon induced stripe formation and charge ordering in high-T-c superconductors

Two recent experimental findings on the formation of stripes in high-temper ature superconductors show that substantial lattice effects are involved in the onset of stripe formation. Huge phonon anomalies have been observed at finite q-vector where this q-value correlates with doping. In addition, a giant isotope effect on the onset temperature T* for stripe formation has b een reported recently. We show here that the striped phase can be caused by a strong nonlinear electron-phonon interaction which yields dynamical char ge ordering on a mesoscale length scale and in a limited time range. A larg e isotope effect on T* is obtained together with substantial phonon anomali es.