In a recent study of the optical conductivity of the Bi-2212 high temperature
superconductor, Hwang, et al. have confirmed the mass-renormalization changes
observed in ARPES but find that such changes are no longer observed in the
highly overdoped regime. In a comment on this study, Cuk, et al. challenge this
conclusion and present ARPES evidence for a kink in the superconducting state
in the highly overdoped regime. We show, however that two doping dependent
properties in the data of Cuk et al., the frequencies of the superconducting
gap and the Van Hove singularity, suggest a Tc that is higher than the 58 K
quoted, and that their sample is not as highly overdoped as claimed. As a
result, these data can not refute the claim of Hwang et al. that the kink is
absent in the highly overdoped region.
