Impurity-effect on the electronic structure in Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+\delta }$ studied by angle-resolved photoemission spectroscopy

We studied the impurity effect on the electronic structure near the Fermi level in Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+\delta }$ by high-resolution angle-resolved photoemission spectroscopy to clarify the origin of dispersion kink in high-$T_{c}$ superconductors. We found that the dispersion kink at the off-nodal region is significantly suppressed by Zn or Ni impurity while that at the node is less affected. The impurity-induced change of the self-energy and its temperature dependence show a good correspondence to those of the magnetic excitation of $Q$ = ($\pi $, $\pi )$, suggesting that electrons are strongly coupled to the spin fluctuation at the antinodal region.