Nonlocal Coulomb Interaction in Mixed-Valence Material LiCu<sub>2</sub>O<sub>2</sub>.

Park, Ina; Jang, Bo Gyu · Nano Lett · 2025

basic_science · Level V

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Abstract

The nonlocal Coulomb interaction is known to play a key role in electronic instabilities, such as charge ordering or superconductivity. In this study, we extend its significance to mixed-valence systems by investigating LiCu<sub>2</sub>O<sub>2</sub>, where the mixed valency arises intrinsically from its own crystal structures. Using <i>ab initio</i> approaches incorporating extended Hubbard interactions, we successfully reproduce the unprecedented bandwidth enhancement observed in LiCu<sub>2</sub>O<sub>2</sub> with respect to the conventional density functional theory prediction. Our comprehensive study, employing various levels of Hubbard corrections, highlights the decisive role of intersite Coulomb interaction in governing Cu d-ligand p hybridization and the resulting electronic structure. This work not only elucidates the fundamental impact of intersite Coulomb interactions in mixed-valence materials but also establishes a reliable framework for their accurate theoretical description.