Variable electron correlation in high-quality MBE- and PLD-grown SrRuO$_{3}$ thin films.

We show that systematic variations in the degree of correlation can occur within SrRuO$_{3}$ as a function of disorder/off-stoichiometry. In particular, we find that one source of disorder can be controlled in SrRuO$_{3}$ thin films by varying the deposition conditions or the deposition technique. Specifically, we clearly demonstrate that variation of vacancies on the ruthenium site gives rise to a variation in correlated behavior as seen in the photoemission spectra (XPS and UPS),. Moreover, the transport properties of our samples are clearly linked to their photoemission spectra, and independently the crystal unit cell parameters. SrRuO$_{3}$ appears to be a system where these effects can be studied in a more systematic fashion, usually not easily accessible, but we suspect that the underlying physics is generic in complex oxidesWork supported by the DoE BES and EPRI.