DFT-based comparative analysis of elastic, electronic, optical, and dynamic properties of PbS and PbSe crystals

This study presents a comprehensive comparative analysis of the elastic, electronic, optical, and dynamic properties of lead chalcogenide semiconductors, lead sulfide (PbS) and lead selenide (PbSe), using density functional theory calculations. The structural stability and mechanical behavior were evaluated through elastic constants, revealing contrasting anisotropy and stiffness profiles. Electronic band structures and density of states highlighted significant differences in bandgap characteristics and carrier mobility potential. Optical investigations, including photoconductivity, absorption coefficient, reflectivity, and dielectric functions demonstrated PbSe’s superior responsiveness in the ultraviolet range, while PbS exhibited more subdued optical activity, making it better suited for infrared applications. Dynamic properties such as phonon dispersion and density of states provided insights into lattice vibration modes and thermal transport tendencies. These multi-property comparisons underscore the functional versatility of PbS and PbSe and guide their suitability for optoelectronic, thermoelectric, and photonic applications.