Discovery of Electrides in Electron-Rich Non-Electride Materials via Energy Modification of Interstitial Electrons

With the discovery of electrides, many electron-rich materials are reported to be non-electrides due to the lack of electride characteristics. Up to date, only a few studies have been done to alter the electronic structures of these materials. In this work, through atom replacement, the energy of interstitial electrons in a non-electride Hf₅Si₃ is successfully modified and a hitherto unknown electride Ca₃Hf₂Si₃ is obtained. It is revealed that the formation of the electride has a strong link to the neighboring cations of interstitial electrons. Moreover, an essential principle for the electride formation in the multi-cations materials is proposed, and 34 dynamically stable ternary electrides are obtained through the proper atom replacement in 29 binary non-electrides materials. The general realization of electrides in the electron-rich non-electrides can greatly expand the research scope of electrides.