Electronic structure, mechanical and optical properties of TiAl3 (L12 & D022) via first-principles calculations

Abstract

Density functional theory based ab initio calculations have been performed to study the electronic structure, mechanical and optical properties of the L12 and D022 phases in TiAl3 intermetallic alloy system. For electronic structures, bonding, and optical properties calculations we used orthogonalized linear combination of atomic orbitals method, while for mechanical properties, Vienna ab initio simulation package (VASP) is used. The band structure calculations show same number of bands crossing the Fermi level in both the L12 and D022 phases. the total density of states (TDOS) spectra reveal that the bottom of conduction band is dominated by Ti, while top of valence band being contributed mostly by Al atoms in both the phases. In the D022 phase, the TDOS at the Fermi level N(EF) are 5.51 while in the L12 phase are 4.67 states/eV formula unit. Localization index calculations reveal that there exist highly localized states above the Fermi level. Results of elastic stiffness constants and bulk mechanical properties are in good agreement with the reported experimental data in literature for both the phases. Optical conductivity spectra in both the phases are rich in structures with the most prominent peak existing at 4.80 eV.