Highly anisotropic anomaly in the dispersion of the copper-oxygen bond-bending phonon in superconducting YBa2Cu3O7 from inelastic neutron scattering

Motivated by predictions of a substantial contribution of the "buckling'' vibration of the CuO2 layers to d-wave superconductivity in the cuprates, we have performed an inelastic neutron scattering study of this phonon in an array of untwinned crystals of YBa2Cu3O7. The data reveal a pronounced softening of the phonon at the in-plane wave vector q = (0, 0.3) upon cooling below similar to 105 K, but no corresponding anomaly at q = (0.3,0). 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 d-wave superconductivity. © 2011, American Physical Society.

Keywords

Superconductors, Oxides, Spin, Symmetry, Layers, Neutrons

Citation

Raichle, M., Reznik, D., Lamago, D., Heid, R., Li, Y., Bakr, M., Ulrich, C., Hinkov, V., Hradil, K., Lin, C. T., & Keimer, B. (2011). Highly anisotropic anomaly in the dispersion of the copper-oxygen bond-bending phonon in superconducting YBa2Cu3O7 from inelastic neutron scattering. Physical Review Letters, 107(17), 177004. doi:10.1103/PhysRevLett.107.177004