Abstract
Electron-phonon interaction in copper oxide superconductors is still enigmatic. Strong coupling for certain optic phonons is now well established experimentally, but a theoretical understanding is challenging. Scattering of electrons near the Fermi surface by the longitudinal acoustic (LA) phonons is expected from basic theory because these phonons modulate electron density. We used inelastic neutron scattering on a large single-crystal sample of optimally doped Bi2Sr2CaCu2O8+δ to show that low-energy LA phonons could couple to electronic density fluctuations only at small phonon wave vectors, which naturally limits any interaction to forward scattering. Such scattering should not be pair-breaking in the case of the d-wave gap. We also found that the previously reported low-energy phonon spectral weight half-way to the zone boundary is consistent with conventional lattice dynamics and does not reflect an incipient charge density wave.
| Original language | English |
|---|---|
| Article number | 144502 |
| Journal | Physical Review B |
| Volume | 100 |
| Issue number | 14 |
| DOIs | |
| State | Published - Oct 4 2019 |
Funding
A.M.M. and D.R. were supported by the DOE, Office of Basic Energy Sciences, Office of Science, under Contract No. DE-SC0006939. G.D.G. was supported by the Office of Basic Energy Sciences (BES), Division of Materials Sciences and Engineering, US Department of Energy (DOE), under Contract No. DE-SC0112704. A portion of this research used resources at the High Flux Isotope Reactor, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. A portion of this work is based upon experiments performed at the TRISP instrument operated by MPG at the Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II), Garching, Germany.