Abstract
The volume dependence of the total energy of LiAlSi compounds in three hypothetical cubic cF12 structures with F4¯3m symmetry are calculated within the local-density approximation. Predictions of structural stability agree with observations. The bonding in the stable structure, where Al and Si form a zinc-blende substructure and Li and Al are arranged in a NaCl substructure, is characterized by strong covalent AlSi bonds. The band structure is very similar to that of pure Si. Trends in the calculated physical properties of the series, Si, LiAlSi, LiAl, are discussed. Structural phase transitions and insulator-metal-insulator transitions in LiAlSi under pressure are predicted.