Photoemission kinks and phonons in cuprates

TL;DR

This paper challenges previous theoretical calculations by demonstrating that phonons significantly influence electronic dispersion in cuprates, suggesting electron-phonon interactions are more important for high-temperature superconductivity than previously thought.

Contribution

The study shows that prior calculations underestimated the impact of phonons on electronic dispersion, highlighting the need to reconsider electron-phonon coupling in cuprate superconductors.

Findings

Phonons have a large influence on electronic dispersion in cuprates.

Previous calculations failed to reproduce experimental electron-phonon coupling effects.

Electron-phonon interactions are more significant for high Tc superconductivity than previously believed.

Abstract

One of the possible mechanisms of high Tc superconductivity is Cooper pairing with the help of bosons, which change the slope of the electronic dispersion as observed by photoemission. Giustino et al. calculated that in the high temperature superconductor La1.85Sr0.15CuO4 crystal lattice vibrations (phonons) should have a negligible effect on photoemission spectra and concluded that phonons do not play an important role. We show that the calculations employed by Giustino et al. fail to reproduce huge influence of electron-phonon coupling on important phonons observed in experiments. Thus one would expect these calculations to similarly fail in explaining the role of electron-phonon coupling for the electronic dispersion.