Alkaline-Earth Metal Effects on Physical Properties of Ferromagnetic AVO (A = Ba, Sr, Ca, and Mg): Density Functional Theory Insights.

The effects of alkaline-earth metals on electronic, optical, thermodynamic, and physical properties of ferromagnetic AVO (A = Ba, Sr, Ca, and Mg) have been investigated by first-principles calculations within the GGA+ formalism based on density functional theory. The optimized structural parameters are in good agreement with the available experimental results that evaluate the reliability of our calculations. The cell and mechanical stability is discussed using the formation energy and Born stability criteria, respectively. The mechanical behaviors of AVO are discussed on the basis of the results of elastic constants, elastic moduli, Peierls stress, and Vickers hardness. The nature of the ductile-brittle transition of AVO compounds was confirmed by the values of Pugh's ratio, Poisson's ratio, and Cauchy pressure. The electronic band structures, as well as density of states, reveal the half-metallic behavior of BaVO and SrVO. However, CaVO and MgVO exhibit spin-gapless and magnetic semiconductor characteristics, respectively. The microscopic origin of the transition from the half-metallic to semiconductor nature of AVO is rationalized using electronic properties. The presence of covalent, ionic, and metallic bonds in AVO compounds is found by the analysis of bonding properties. The single-band nature of half-metallic AVO is seen by observing hole-like Fermi surfaces in this study. Furthermore, the various thermodynamic and optical properties are calculated and analyzed. The refractive index suggests that AVO could be a potential candidate for applications to high-density optical data storage devices.