Exploring the Coexistence Conditions and Intrinsic Relationships between Electrides, Superconductivity, Kagome Lattice, and Superionic Behaviors in Li–Ge Compounds

Abstract

A systematic prediction of crystal structures of the Li x Ge (x = 1−8) system is performed using a combination of structure prediction and ab initio calculations coupled with deep learning methods. The structural features are discussed in terms of high-coordination and layered structures. The Dirac cones, flat bands, and van Hove singularities in the Kagome lattice formed by interstitial quasi-atoms, Li, and Ge atoms are explored. The superconductivity of the Li 5 Ge-P6/mmm is also predicted at 0−100 GPa. The deep learning simulations revealed that the Ge atoms in the Li 5 Ge-P6/mmm remained solid at 0 GPa and 400 K, while the Li atoms melted and entered a superionic state. Finally, the P-T phase diagram of Li 5 Ge-P6/mmm is presented at pressures from 0 to 100 GPa. Our results indicate that the layered and high coordination structures in Li-rich compounds provide an excellent platform for understanding the abundant physical properties and their coexistence.