Kink in the Dispersion of Layered Strontium Ruthenates

Abstract

We present detailed energy dispersions near the Fermi level along the high symmetry line $\Gamma X$ on the monolayer and bilayer strontium ruthenates ${\mathrm{S}\mathrm{r}}_2{\mathrm{R}\mathrm{u}\mathrm{O}}_4$ and ${\mathrm{S}\mathrm{r}}_3{\mathrm{R}\mathrm{u}}_2{\mathrm{O}}_7$, 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.