Metallic Nature and Optical Anisotropy in CsLa: A CASTEP‐Based Investigation

We highlight a theoretical investigation of the structure, electronic states, and optical response of the polar intermetallic complex CsLa in this article. The proposed hexagonal noncentrosymmetric structure has been optimized using density functional theory (DFT) in the framework of GGA and Perdew–Burke–Ernzerhof (PBE), demonstrating a small expansion and a comparatively low bulk modulus—features that represent mechanical softness. Density of states (DOS) and band structure calculations clearly establish metallic conductivity, dominated by La–5d and Cs–5p orbital contributions at the Fermi level. Significant anisotropy is revealed by optical analysis: reflectance, absorption spectra, and dielectric constants are all significantly changed with crystallographic orientations. Additionally, efficient charge transport and directional energy dissipation properties can be achieved by high static dielectric values and clear, relatively small energy absorption peaks. These characteristics suggest that CsLa might be applicable in energy conversion devices, high‐k dielectric applications, and infrared photonics. Overall, CsLa emerges as a promising candidate for multifunctional optoelectronic materials due to its symmetry‐breaking geometry combined with metallic conductivity and anisotropic optical response.