First-principles study of the structural, electronic and elastic properties of ternary Zr₂AN (A = Ga, in and Tl)

The structural, electronic and elastic properties of ternary Zr ₂AN (A = Ga, In and Tl) ceramics have been studied by first-principles calculations. The obtained lattice parameters are in agreement with available data. The computed lattice parameters increase with increasing the atomic radii for A elements, whereas the cohesive energies and Debye temperatures decrease accordingly. The band structure shows that these three ceramics are all conductive. The density of states at the Fermi level (E _f) mainly originates from Zr d state with a minor contribution of A p states. Below E_f, the hybridization peak of Zr d-N p lies in lower energy range which indicates that Zr-N bond is stronger than Zr-A bond. The charge density distribution shows that Zr and N atoms form a strong Zr-N-Zr covalently bonded chain.