@article{121346,
  author = {D. Reznik and B. Keimer and F. Dogan and I.A. Aksay},
  title = {Q-Dependence of Self-Energy Effects of the Plane Oxygen Vibration in YBa2Cu3O7},
  abstract = { We have measured the temperature dependence of the peak position and linewidth of the 42.5 meV phonon branch in a twinned single crystal of YBa2Cu3O7 as a function of wave vector q. In the (100)/(010) direction in the Brillouin zone, considerable softening and broadening occur below the superconducting transition temperature T-c at some values of q. We observe an order of magnitude smaller softening and no linewidth broadening for q in the (110)/(1(1) over bar0$) direction. Possible implications of these findings for the symmetry of the superconducting order parameter are discussed. },
  year = {1995},
  journal = {Physical Review Letters},
  volume = {75},
  pages = {2396-2399},
  month = {09/1995},
  isbn = {0031-9007},
  language = {eng},
}