First-Principles Study of Dimensionality Evolution of Electrides under Pressure

Electrides are a novel class of quantum materials that challenge traditional theories of chemical bonding, offering transformative potential in advanced fields such as superconductivity and low-power electronics. The different electron distribution in two-, one-, and zero-dimensional electrides leads to distinct properties. In this study, we demonstrate the dimensional evolution of electrides by applying hydrostatic pressure, a common method for tuning electronic structure. Through systematic calculations on representative electrides, we observe that the localization of anionic electrons under pressure follows similar patterns across different dimensionalities. For two- and one-dimensional electrides, increasing pressure enhances the localization of anionic electrons, leading them to concentrate toward the center, suggesting a transition toward zero-dimensional states. Analysis of the local potential function reveals that this evolution is induced by pressure-mediated anisotropic compression of the interstitial structure, which amplifies the potential difference between localized and delocalized anionic electrons. In contrast, the distribution pattern of anionic electrons in zero-dimensional electrides shows minimal change, with the proportion varying depending on the specific material system. Our findings indicate that under pressure, electrides generally evolve toward more isolated anionic electron states. This study provides new insights into the dimensional evolution and electron localization behavior of pressurized electrides, establishing a theoretical foundation for designing electrides with controlled dimensionality.