Q-Dependence of Self-Energy Effects of the Plane Oxygen Vibration in YBa₂Cu₃O₇

Date Published:

Sep

Type of Article:

Article

ISBN Number:

0031-9007

Accession Number:

WOS:A1995RU81100036

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.