The isotope effect (IE) on Tc of optimally doped HTSCs (α=dlnTc/dlnM <0.1) is small in comparison with the conventional BCS superconductors (α~0.5), an evidence that usually used against the phonon mediated pairing in HTSCs. However, the ARPES kink is one of the strongest evidence that there is strong electron-phonon coupling in HTSCs. To confirm this, [...]
