Etude des propriétés physiques de quelques composés intermétalliques binaires de type AB3

Abstract

This thesis presents a first-principles study of the structural, electronic, and optical properties of selected binary intermetallic compounds of type AB₃, using Density Functional Theory (DFT). The aim is to provide a fundamental understanding of these materials and assess their potential applications in optoelectronics, energy storage, and catalysis. The study begins with an overview of semiconductor physics, emphasizing the role of band structures, optical transitions, and mechanical stability in determining material performance. Next, a detailed computational methodology is introduced, describing the use of DFT-based simulations, pseudopotential methods, and exchangecorrelation functionals to accurately predict material properties.The investigation focuses on transition metal halides (WClₓ, x = 3 to 6) and an organic crystal (4C16H10Br2O2). The results show that β-WCl₆ and α-WCl₆ exhibit direct band gaps and strong UV-visible absorption, making them suitable for photodetectors and solar cells. Meanwhile, WCl₄ displays metallic properties, suggesting applications in conductive coatings and catalysis. The study of the organic compound 4C16H10Br2O2 reveals high refractive indices and strong absorption in the UV-visible range, indicating potential use in nonlinear optics and organic electronic devices. Overall, this work provides valuable insights into the fundamental properties of AB₃-type intermetallic compounds and highlights their potential for next-generation optoelectronic and energy applications. Future research could focus on doping effects, temperature stability, and experimental validation to further optimize their performance.