Doping Dependence of the Mass Enhancement in(Pb,Bi)2Sr2CaCu2O8at the Antinodal Point in the Superconducting and Normal States

Angle-resolved photoemission spectroscopy is used to study the mass renormalization of the charge carriers in the high-${T}_{c}$ superconductor $(\mathrm{P}\mathrm{b},\mathrm{B}\mathrm{i}{)}_{2}{\mathrm{S}\mathrm{r}}_{2}{\mathrm{C}\mathrm{a}\mathrm{C}\mathrm{u}}_{2}{\mathrm{O}}_{8}$ in the vicinity of the $(\ensuremath{\pi},0)$ point in the superconducting and the normal states. Using matrix element effects at different photon energies and due to a high momentum and energy resolution the bonding and the antibonding bands could be separated in the whole dopant range. A huge coupling to a bosonic collective mode is observed below ${T}_{c}$ for both bands, in particular, for the underdoped case. Above ${T}_{c}$, a weaker coupling to a continuous spectrum of modes is detected.