Low energy kink in the band dispersions of Sr$_{2}$RuO$_{4}$ studied by ARPES

In Sr$_{2}$RuO$_{4}$ , incommensurate antiferromagnetic fluctuations (IAF) were reported to have 4 - 10 meV energy with \textbf{q} = (0.6$\pi $, 0.6$\pi )$ while the lowest optical phonon is at 12meV. If an electron is coupled to AIF in Sr$_{2}$RuO$_{4}$, the electronic band dispersions will kink below 10meV. Then, one can attribute the low energy kinks below 10meV to the electron-IAF coupling. In spite of the fact that multiple kink energies were recently reported in Sr$_{2}$RuO$_{4}$, kinks below 10meV has not been observed. To look for the so far unobserved electron-IAF coupling in Sr$_{2}$RuO$_{4}$, we performed ultra high resolution angle resolved photoemission (ARPES) experiments on Sr$_{2}$RuO$_{4}$ with clean surfaces. In the results, we observe kinks in the band dispersions at energies below 10 meV which show strong momentum dependence. To elucidate the origin of these new kinks, we compare ARPES results with inelastic neutron scattering and band calculation results.