Impact of film thickness on the geometric and electronic characteristics of ultrathin rutile‐ <scp> TiO ₂ </scp> (110) films supported by metal substrates

Abstract Titanium dioxide (TiO 2 ) has received significant attention due to its importance in a wide range of applications, including photocatalysis, solar energy conversion, and chemical sensing. The physicochemical properties of TiO 2 can be finely tuned using a novel platform of ultrathin oxide films. In this study, a computational study based on density functional theory (DFT) calculations is performed to investigate the thickness‐dependent geometric and electronic properties of ultrathin rutile‐phase TiO 2 (110) films supported by five body‐centered cubic metal substrates: W, Mo, Ta, Nb, and V, oriented along the (100) plane. The DFT calculations suggest that W and Mo may serve as optimal metal substrates for the formation of ultrathin TiO 2 films, in which lattice mismatch along the long axis plays a significant role. Furthermore, the interfacial electronic structure of the TiO 2 film, primarily characterized by charge transfer from metal to the TiO 2 layer and the formation of metal‐included gap states (MIGS), can be used to rationalize the thickness‐dependent variation in the work function of ultrathin TiO 2 films on metal substrates. Our results provide valuable insights into the effect of the film thickness on the geometric and electronic properties of TiO 2 films grown on metal substrates.