Abstract
We report the first measurement of the Cu-O bond stretching phonon dispersion in optimally doped using inelastic x-ray scattering. We found a softening of this phonon at from 76 to 60 meV, similar to the one reported in other cuprates. A comparison with angle-resolved photoemission data on the same sample revealed an excellent agreement in terms of energy and momentum between the angle-resolved photoemission nodal kink and the soft part of the bond stretching phonon. Indeed, we find that the momentum space where a kink is observed can be connected with a vector with , corresponding exactly to the soft part of the bond stretching phonon.
- Received 28 September 2007
DOI:https://doi.org/10.1103/PhysRevLett.100.227002
©2008 American Physical Society