Abstract
Motivated by predictions of a substantial contribution of the “buckling” vibration of the layers to -wave superconductivity in the cuprates, we have performed an inelastic neutron scattering study of this phonon in an array of untwinned crystals of . The data reveal a pronounced softening of the phonon at the in-plane wave vector upon cooling below , but no corresponding anomaly at . Based on the observed in-plane anisotropy, we argue that the electron-phonon interaction responsible for this anomaly supports an electronic instability associated with a uniaxial charge-density modulation and does not mediate -wave superconductivity.
- Received 3 May 2011
DOI:https://doi.org/10.1103/PhysRevLett.107.177004
© 2011 American Physical Society