Half-Metallic Chalcogenide Perovskites XKS 3 : Ab Initio Design for Spintronic and UV-Shielding Technologies

The structural, electronic, magnetic, and optical properties of XKS 3 (X = Ba, Ca, Sr, Ra) compounds are systematically investigated using first-principles calculations within the generalized gradient approximation. The compounds are found to exhibit stable crystal structures with distinct electronic and magnetic characteristics across the series. The calculated electronic structures reveal semiconducting behavior accompanied by significant spin-dependent electronic features, indicating the potential of these materials for spin-polarized applications. The magnetic properties are further analyzed in terms of the calculated magnetic moments and exchange interactions. In addition, the optical spectra demonstrate pronounced responses in the ultraviolet region, suggesting possible relevance to future optoelectronic and photonic applications. The systematic variation of the structural, electronic, magnetic, and optical properties with the X-site cation provides useful insight into the tunability of this family of compounds. Overall, the results identify XKS 3 compounds as promising candidates for further theoretical and experimental investigation in spintronic and optoelectronic technologies.