Density Functional Theory Analysis of Structural and Electronic Properties of IV–VI Semiconductors: PbSe, PbS, and PbSe₁₋ₓSₓ Alloys

This study presents first-principles calculations performed within the framework of density functional theory (DFT) using the full-potential linearized augmented plane wave (FP-LAPW) method as implemented in WIEN2k. Exchange–correlation interactions are described through the Wu–Cohen generalized gradient approximation (WC-GGA), while the modified Becke–Johnson (mBJ) potential is applied to improve the accuracy of the electronic band gap. The analysis initially focuses on the structural and electronic properties of PbS and PbSe in their NaCl-type phase. The results confirm that both compounds exhibit a direct band gap located at the L point. The investigation then extends to the ternary PbSe₁₋ₓSₓ alloys, where the influence of composition on lattice parameters and bulk modulus is systematically examined. The findings reveal clear deviations from Vegard’s law, interpreted within the theoretical framework proposed by Zunger and co-workers. Furthermore, the dependence of the band gap on alloy composition is analyzed under different pressure conditions. In addition to electronic properties, the optical response is also explored, including the dielectric function, refractive index, absorption coefficient, and reflectivity, highlighting the potential of these materials for optoelectronic and photovoltaic applications.

• lead selenide
• lead sulfide
• IV-VI semiconductors
• rock salt structure
• direct band gap
• lattice parameters
• bulk modulus
• Vegard's law deviation
• pressure dependence of band gap
• optical properties
• dielectric function
• refractive index
• absorption coefficient
• reflectivity
• optoelectronic materials
• photovoltaic materials

• Advanced Chemical Physics Studies
• Chalcogenide Semiconductor Thin Films
• 2D Materials and Applications
• lead selenide
• lead sulfide
• IV-VI semiconductors
• rock salt structure
• direct band gap
• lattice parameters
• bulk modulus
• Vegard's law deviation
• Atomic and Molecular Physics, and Optics
• Electrical and Electronic Engineering
• Materials Chemistry
• Physics and Astronomy
• Engineering
• Materials Science