The ab initio calculations of the doping Zr's influence on the electronic structure of AlCo2Ti

The electronic structures of the ternary (Hume-Rothery) L2₁-phase compound AlCo₂Ti are calculated by first-principles using full potential linearized augmented plane wave (FLAPW) method with the generalized gradient approximation (GGA). The ab initio results are analyzed with a simplified model for Al-based compounds containing transition metal (TM) atoms. The results show that the total DOS depends strongly on the positions of TM atoms, and the TM d DOS plays a crucial role in hybridization with other element valence electrons. However, the Al 3s states are repelled far away from the Fermi energy in studied sample, and the Al 3d states are far more extended-like in the character than the d states. Furthermore, the total DOS_s are modulated by Al 3p states and the Al 3p states are more sensitive than d states to change in the electronic interactions. Then, the Al 3p is also important for the ternary stability of the intermetallic compound. The Co-Ti interaction becomes stronger by the doping element Zr in the Al₄Co₈Ti₃Zr structure. Especially, the doping Al₄Co₈Ti₃Zr alloy has a larger value DOS at the Fermi level and makes the total DOS gap smaller than the AlCo₂Ti.