First principles studies on structural, elastic, acoustic, and optoelectronic properties of hexagonal calcium oxide (CaO)

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Motivated by the comprehensive research on the optoelectronic properties of hexagonal phases of metal oxides, this study focused only on nanomaterials that resemble with hexagonal structure but are not carbon-based. The researchers investigated various features and phenomena related to these materials. This study concentrated on the study of the structural, elastic, acoustic, and optoelectronic properties of hexagonal calcium oxide (CaO). We have used the comparative approach of exchange-correlation functionals by employing GGA (PBE, RPBE, PW91, WC, and PBESOL) and LDA (CA-PZ to study the desired properties. The highest band gap 3.49 eV is attained with GGA–PBESOL at an optimized 500 eV cut-off energy. Research into the elastic constants, (bulk, shear and Young's) modulus, (Poisson and Pugh) ratio, and elastic anisotropy revealed that CaO is a ductile, elastically anisotropic, and mechanically stable material. The results obtained of the dielectric properties confirm the charge-storing capacity of CaO. The findings of this study will provide insights into the fundamental properties of CaO, which can be useful for applications of CaO in sensors, catalysis, and energy storage devices.