Momentum dependence of the electron-phonon coupling and self-energy effects in YBa_2Cu_3O_7 within the local density approximation

Abstract

Using the local density approximation (LDA) and a realistic phonon spectrum we determine the momentum and frequency dependence of ${\alpha }^{2}F(\mathbf{k},\omega )$ in YBa${}_2$Cu${}_3$O${}_7$ for the bonding, antibonding, and chain band. The resulting self-energy $\Sigma$ is rather small near the Fermi surface. For instance, for the antibonding band the maximum of $Re\Sigma$ as a function of frequency is about 7 meV at the nodal point in the normal state and the ratio of bare and renormalized Fermi velocities 1.18. These values are a factor 3-5 too small compared to the experiment showing that only a small part of $\Sigma$ can be attributed to phonons. Furthermore, the frequency dependence of the renormalization factor $Z(\mathbf{k},\omega )$ is smooth and has no anomalies at the observed kink frequencies which means that phonons cannot produce well-pronounced kinks in stoichiometric YBa${}_2$Cu${}_3$O${}_7$, at least, within the LDA.

Figure 1 slightly revised, text shortened, accepted as a PRL

References in corpus (1)

• Laser ARPES, the sudden approximation, and quasiparticle-like peaks in Bi2Sr2CaCu2O8+delta

Cited by in corpus (1)

• Electron-phonon coupling in a two-dimensional inhomogeneous electron gas: consequences for surface spectral properties