Structural,elastic and optoelectronic properties of the hydrogen based perovskite compounds: Ab-initio study

The structural, elastic, electronic and optical properties of the cubic CaMH₃ (M=Ni and Pd) compounds are investigated using first principle calculations based on the density functional theory (DFT) as implemented in the Wien2k code. The calculated lattice constants are found to be in good agreement with the values reported in the previous literature. The analysis of standard enthalpy of formation shows that both CaNiH₃ and CaPdH₃ are thermodynamically stable. The bulk modulus and cohesive energy values indicate that CaNiH₃ is less compressible and more rigid than CaPdH₃. The bonding forces between atoms of the studied compounds are mainly ionic and partially covalent. The real and imaginary parts of the dielectric function are used to calculate the optical properties. The partial density of states for the present compounds are used to explain the main peaks of the optical spectra. Beneficial optoelectronic applications are predicted from the analysis of the optical spectra of CaNiH₃ and CaPdH₃ compounds.