FIRST-PRINCIPLES STUDY OF THE STRUCTURAL, ELECTRONIC, AND ELASTIC PROPERTIES OF HYDRIDE PEROVSKITES XCAH₃ (X = NA, K, RB,CS) UNDER PRESSURE
DOI:
https://doi.org/10.18623/rvd.v22.n2.3223Keywords:
Perovskites, Structural, Elastic, Electronic, DOS, Density Functional Theory (DFT), FP-LAPW, GGAAbstract
This study is a thorough investigation. It is founded on fundamental ideas. Density functional theory is what we employ. Structural, electronic, and elastic properties of the hydride perovskites XCaH₃ (where X = Na, K, Rb, and Cs) have been investigated using DFT. Through energy–volume optimisation, equilibrium Lattice Constants were determined, demonstrating their stability in the cubic perovskite phase. The electronic band structures and density of states of all compounds indicate that they exhibit semiconducting behavior with direct band gaps. The estimated band gap energies are 3.14 eV for CsCaH₃, 3.29 eV for KCaH₃, 3.35 eV for RbCaH₃, and 2.51 eV for NaCaH₃.This suggests that the ion radius of the A-site cation gradually increases up to Rb, after which it slightly decreases for Cs. The Born stability criteria for the elastic constants verify that these perovskites are mechanically stable in ambient conditions. Additionally, the determined Young's, shear, and bulk moduli show that these hydrides are ductile and have sufficient mechanical strength. These findings provide important new insights into the fundamental behavior of XCaH₃ hydrides, which could be beneficial for future energy-related technology applications.
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