Anomalous suppression of energy gap near the antinode in Bi2212

An energy gap holds special importance in the study of high-$T_c$ superconductors (HTSC) as it is often associated with the order parameter of complex phases in these materials. In hole-doped cuprates around optimal doping, past experiments suggest the presence of two momentum-anisotropic energy gaps originating from $d$-wave superconductivity and pseudogap. Here we report an anomalous energy gap suppression near the antinode in overdoped Bi2212 that persists from $T \ll T_c$ to $T > T_c$. Our data imply that the suppression may not originate from pair-breaking scattering, but can be phenomenologically described by higher harmonics of a $d$-wave gap. It is important to uncover the origin of this suppression, which is instrumental in understanding the complex landscape of interacting order parameters in cuprate HTSCs.