A Density Functional Prediction on Phase Stability, Optical, Elastic and Thermal Properties of Metallic CuZr Intermetallic Compound

Abstract

An ab-initio investigation on structural, electronic, optical, elastic and thermal properties of CuZr intermetallic compound using full-potential linearized augmented plane wave method in the support of density functional theory at ambient condition have been performed. We have employed the generalized gradient approximation of (PBE) to indulgence the exchange correlation potential by solving Kohn-Sham equations. Total energy of CuZr as a function of the unit cell volume has been calculated using full potential linearized augmented plane wave (FP-LAPW) method in B1, B2 and B3 crystal structure to obtain the ground state properties. The study of different phases regarding their enthalpy vs. pressure variation is also presented. Our calculated structural parameters (a0 = 3.268 Å, B = 119 GPa and B' = 4.95) of CuZr are consistent with both the available experimental (a0 = 3.262 Å) and previously presented theoretical data (a0 = 3.280 Å, B = 121 GPa) for B2-type (CsCl) crystal structure. The results obtained from density of states (DOS) and optical spectra shows that the present compound is metallic. The value of density of states at the Fermi level N (EF) is found to 3.89 states/eV which is determined due to the contribution of ‘d’ like states of Cu and Zr and ‘p’ like states of Zr atom. The second order elastic constants are comparatively studied and an excellent agreement is found with other theoretical data. The trend of calculated elastic constants i.e. C11 - C12 > 0, C11 > 0, C44 > 0, C11 + 2C12 > 0 shows the stability criteria for B2-type (CsCl) crystal structure at ambient pressure. The sound velocities for longitudinal and shear waves, Debye average velocity and Debye temperature have been successfully calculated as a first theoretical prediction.