Study of phonon anomalies in stripe phase of high T_c cuprates

We theoretically investigate phonon anomalies in various high T _c cuprates in terms of stripe concept. They could be caused by coupling with charge translational modes of stripes. The phonon self-energy correction is evaluated by taking into account the collective stripe modes. The coupling with stripes causes a phonon dispersion gap when the phonon dispersion has a steep slope around 2Q. No gap appears when the phonon spectrum has a flat dispersion around 2Q. Thus it turns out that these are depending on the slope of the phonon dispersions.