Forward scattering peak in the electron–phonon interaction and impurity scattering of cuprate superconductors

Abstract

AbstractThe important role of the electron–phonon interaction (EPI) in explaining the normal state properties and pairing mechanism in high‐Tc superconductors (HTSC) is discussed. A number of experiments are analyzed such as: dynamical conductivity, Raman scattering, neutron scattering, ARPES, tunnelling measurements, and etc. They give convincing evidence that the EPI dominantly contributes to pairing in HTSC oxides. Strong electronic correlations cause the forward scattering peak (FSP) in the EPI and in the non‐magnetic impurity potential. The theory based on the FSP (whatever is its origin) explains several puzzling experimental results in ARPES and transport: (1) much smaller transport coupling constant than the pairing one (λtr ≪ λph); (2) the ARPES non‐shift puzzle – where the nodal kink at 70 meV is unshifted in the superconducting state while the anti‐nodal one at 40 meV is shifted; (3) d‐wave superconductivity due to the EPI; (4) robustness of d‐wave pairing in the presence of nonmagnetic impurities; (5) collapse of the elastic scattering rate near the anti‐nodal point in the superconducting state; (6) anomalous temperature dependence of the Hall angle in optimally doped HTSC. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)