First-principles study of LiAlO$_{2}$ in tetrahedrally and octahedrally coordinated structures

Ultrawide-band gap (UWBG) semiconductors (band gap \textgreater 4 eV) have many potential interesting applications, such as in high-power electronics and deep-UV optoelectronic devices. LiAlO$_{2}$~is a candidate material for UWBG semiconductors. This project is a first-principles electronic structure study of LiAlO$_{2}$, focusing on band gap/band structure, bulk moduli of common crystal structures, and transition pressures between different structures. Specifically, we compare the tetragonal~$\gamma $ and orthorhombic~$\beta $ structures (both tetrahedrally coordinated) with the octahedrally coordinated R-3m~$\alpha $ structure. We calculate these properties using the density functional theory (DFT)-based linearized muffin tin orbital (LMTO) and pseudopotential plane wave methods. We find that the tetrahedrally bonded structures have slightly lower energy than the octahedral one and a transition to the octahedral phase occurs near 1.5 GPa.