Speaker
Description
In Fermi liquids, electron-boson coupling is (EBI) quantified through the Eliashberg function $\alpha^2F(\omega,\mathbf{k})$, which modifies their self-energy $\Sigma(\varepsilon,\mathbf{k})$ obtainable from ARPES. We present a combined ARPES, density-functional theory, and high-resolution electron energy-loss spectroscopy (HREELS) study on the EBI in CaTiO$_3$ (CTO) thin films. CTO hosts a 2-dimensional electron liquid (2DEL) analogous to that in SrTiO$_3$-based surfaces, making both materials technologically appealing for oxide electronics. Our results show that the presence of localized in-gap states changes the dielectric response of the CTO film, red-shifting high-energy phonon modes, thereby indicating their strong coupling to the 2DEL states. Combining ARPES with HREELS is a powerful approach to study quantum materials with strong EBI.
