Electronic Structures of the Filled Tetrahedral Semiconductor Li₃AlN₂

The first-principles total energy calculations with the local density approximation (LDA) and the plane wave pseudopotential method are employed to investigate the structural properties and electronic structures of Li₃AlN₂. The calculated lattice constants and internal coordination of atoms agree well with the experimental results. Detailed studies of the electronic structure and the charge-density redistribution reveal the features of the strong ionicity bonding of Al-N and Al-Li, and strong hybridizations between Li and N in Li₃AlN₂. Our band structure calculation verifies Li₃AlN₂ is a direct gap semiconductor with the LDA gap value of about 2.97eV and transition at G.