Fig. 4

Tuning and disentangling the interplay of electron−phonon and electron−plasmon coupling. a Normalised residual intensity plot of EDCs at the centre of the electron pocket (see Supplementary Fig. 3), revealing a clear satellite structure that shifts to higher binding energy with increasing charge carrier doping. b Fits to the measured raw EDCs reveal that the separation of this satellite from the quasiparticle band follows the functional form of a plasmon mode (see Methods), while an additional weak satellite feature is found to remain at a constant energy for the lower-doped samples, which we attribute to a phonon-induced replica band. Error bars reflect the uncertainty in extracting the Luttinger area and satellite binding energies from the experimental measurements, and incorporate statistical errors in peak fitting as well as systematic experimental uncertainties. c Decomposition of the coupling strength to phonon and plasmon modes from the ab initio calculations reveals a rich carrier-density-driven crossover in the underlying nature of dominant many-body interactions in this system