[en] The interactions between a variety of ultrathin metal overlayers and the TiO₂(110) surface have been the focus of many studies in recent years as part of an effort to understand the chemistry of metal/ceramic interfaces. Aluminum reacts strongly with the stoichiometric, nearly defect-free TiO₂ surface, and we were interested in determining if we could alter this interaction by chemically modifying the TiO₂ surface with potassium prior to Al deposition. Potassium is of interest because of its use as a promoter in oxide-supported catalysis systems. In this article, we present XPS data for the interaction of Al and K (separately) with clean stoichiometric TiO₂, as well as data for the interaction of Al with a TiO₂(110) surface covered with a monolayer of K.copyright 1998 American Vacuum Society