First‐Principles Study of Elastic, Structural, Electronic, Thermodynamical, and Optical Properties of Yttria (Y2O3) Ceramic in Cubic Phase

Structural, elastic, optical, thermodynamical, and electronic properties of yttrium oxide compound in cubic phase have been studied using the full‐potential augmented plane waves ( FP ‐ LAPW ) within density functional theory ( DFT ) framework. Four different approximations were used for exchange‐correlation potentials terms, comprised Perdew–Burke–Ernzerhof generalized parameterization of gradient approximation ( GGA ‐ PBE ), Wu–Cohen ( WC ‐ GGA ), local‐density approximation ( LDA ), and new approximation modified Becke and Johnson ( mBJ ‐ GGA ). The structural properties such as equilibrium lattice parameter, bulk modulus and its pressure derivative have been obtained using optimization method. Moreover, Elastic constants, Young's modulus, shear modulus, Poisson's ratio, sound velocities for longitudinal and shear waves, Debye average velocity, Debye temperature, and Grüneisen parameters have been calculated. Obtained structural, elastic and other parameters are consistent with experimental data. Moreover pressure dependence of the elastic moduli was studied. From electronic calculations, it has been found that the band gap was 5.7 eV at Г point in the Brillouin zone using mBJ ‐ GGA approximation. Optical properties, such as the dielectric function, refractive index, extinction index, and optical band gap, were calculated for radiation up to 14 eV. In addition, the unique type of bonding in Y 2 O 3 was discussed by three method including effective charge, B/G ratio, and charge density distribution.