Unmasking the Origin of Kinks in the Photoemission Spectra of Cuprate Superconductors

The origin of a ubiquitous bosonic coupling feature in the photoemission spectra of high-T-c cuprates, an energy-momentum dispersion kink observed at similar to 70 meV binding energy, remains a two-decade-old mystery. Understanding this phenomenon requires an accurate description of the coupling between the electron and some collective modes. We report here ab initio calculations based on GW perturbation theory and show that correlation-enhanced electron-phonon interaction in cuprates gives rise to the strong kinks, which not only explains quantitatively the observations but provides new understanding of experiments. Our results reveal it is the electron density of states being the predominant factor in determining the doping dependence of the kink size, manifesting the multiband nature of the cuprates, as opposed to the prevalent belief of it being a measure of the mode-coupling strength.

Automated summary

Through ab initio calculations and GW perturbation theory, we found that correlation-enhanced electron-phonon interaction in cuprates leads to the energy-momentum dispersion kinks observed in the spectra, explaining the observations and providing new experimental insights. Our results reveal that the electron density of states is the predominant factor in determining the kink size, demonstrating the multiband nature of cuprates.