First principles calculations of structural, elastic, electronic properties of Ir₃Zr with L1₂ structure under high pressure

The effects of pressure on the structural, elastic and electronic properties of Ir₃Zr are investigated by means of the first-principles calculations based on the density functional theory with generalized gradient approximation and local density approximation methods. The calculated lattice parameters and elastic modulus of Ir₃Zr at zero pressure are in good agreement with available experimental and theoretical results. The values of elastic constants (C₁₁, C₁₂, C₄₄), bulk modulus (B), shear modulus (G), Young modulus (E), Poisson's ratio (υ), anisotropy index (A) and Debye temperature (T_D) present the linearly increasing dependences on the external pressure. Additionally, the B/G values exhibit an upward trend with increasing pressure, which means that higher pressure can improve its ductility. Ir₃Zr exhibits a brittle characteristic at zero pressure. When the pressure reaches 10 GPa, the Cauchy pressure and B/G value show ductile feature. In addition, the pressure-dependence behavior of density of states, Mulliken charge and bond length are analyzed. - Graphical abstract: Display Omitted - Highlights: • The elastic and electronic properties of Ir₃Zr under pressure are investigated. • The elastic constants, elastic moduli increase with the pressure increasing. • When the pressure reaches 10 GPa, Ir₃Zr changes from brittle to ductile. • Ir₃Zr remains as a stable structure and no structural transition under pressure