The role of electronic bandwidth in oxide materials

With the emerging interests in topological materials, high-temperature superconductors, and correlated systems, electronic structures are becoming critical predictive tools. Specifically, flat bands have attracted significant attention as indicators of correlated phenomena and potential unconventional superconductivity. Yet, there is a misunderstanding within the literature that attributes this type of complex physics to trivial flat bands arising from electronic localization in atomic- or molecular-like materials. Here, we study a selection of transition metal oxides ranging from the simple binary oxides like ReO₃ or rutile TiO₂ to battery electrode LiCoO₂ or high-T_c cuprate HgBa₂Ca₂Cu₃O₈ to discuss the importance of electronic dispersion near the Fermi level. We establish a framework for understanding metallicity in these oxides using the real space and electronic structure. While we focus on oxide materials given the diversity of structures and applications, the role of bandwidth is relevant across crystalline inorganic materials.