Kink in the Dispersion of Layered Strontium Ruthenates

We present detailed energy dispersions near the Fermi level along the high symmetry line ΓX on the monolayer and bilayer strontium ruthenates Sr₂RuO₄ and Sr₃Ru₂O₇, determined by high-resolution angle-resolved photoemission spectroscopy. A kink in the dispersion is clearly shown for the both ruthenates. The energy position of the kink and the slope in the low-energy part near the Fermi level are almost identical between them, whereas the dispersion in the high-energy part varies, like the behavior of the kink for the cuprate superconductors.