"Evidence for the Importance of Extended Coulomb Interactions and Forward Scattering in Cuprate Superconductors"

S. Johnston: I. M. Vishik, W. S. Lee, F. Schmitt, S. Uchida, K. Fujita, S. Ishida, N. Nagaosa, Z. X. Shen and T. P. Devereaux; Physical Review Letters, 04/20/12.

Additional Authors: I. M. Vishik, W. S. Lee, F. Schmitt, S. Uchida, K. Fujita, S. Ishida, N. Nagaosa, Z. X. Shen and T. P. Devereaux

Abstract:

The prevalent view of the high-temperature superconducting cuprates is that their essential low-energy physics is captured by local Coulomb interactions. However, this view been challenged recently by studies indicating the importance of longer-range components. Motivated by this, we demonstrate the importance of these components by examining the electron-phonon (e-ph) interaction with acoustic phonons in connection with the recently discovered renormalization in the near-nodal low-energy (∼8–15  meV) dispersion of Bi2Sr2CaCu2O8+δ. By studying its nontrivial momentum and doping dependence we conclude a predominance of forward scattering arising from the direct interplay between the e-ph and extended Coulomb interactions. Our results thus demonstrate how the low-energy renormalization can provide a pathway to new insights into how these interactions interplay with one another and influence pairing and dynamics in the cuprate