First-principles calculations to investigate structural, electronic, optical, elastic and thermodynamic properties of Yb3Q5 (Q=Ge, Si) for energy applications

From the first-principles DFT calculations, we explore the optoelectronic and thermoelectric properties of Yb3Q5 (Q= Ge, Si). The ground state properties of crystalline materials can precisely be estimated using the FP-LAPW technique implemented in the WIEN2K code. It can be determined that the compounds under consideration are metallic based on their band structures. Fermi surfaces of Yb3Q5 (Q= Ge, Si) are also calculated to investigate the electronic conductivity of these materials at the Fermi level. The phenomenon of absorption and dispersion of incident photons can be explained using obtained dielectric function ε(ω) for Yb3Q5 (Q= Ge, Si) compounds. The infrared (IR) region is where Yb3Q5 (Q= Ge, Si) compounds absorb most light packets, however, their absorption in the visible region is also not negligible. These materials are also potential candidates for antireflecting coatings in the upper UV region. Yb3Q5 (Q= Ge, Si) are brittle compounds as their B/G values are less than 1.75. Thermodynamic parameters show that these compounds are thermodynamically stable. © 2023 Elsevier GmbH