A comprehensive numerical investigation on structural stability, mechanical, and optoelectronic properties of HfxSi1‑xO2 tetragonal compounds from the hafnon Family

This numerical research explores the structural stability, phonons, electronic, and optical properties of tetragonal Hf_xSi_1-xO₂ solid solutions for the rates x  = 0.25, 0.5, and 0.75, respectively. During this numerical investigation, the Full-Potential Linearized Augmented Plane Wave method (FP-LAPW) based on the Density Functional Theory (DFT) was employed. Total energy calculations and structure relaxations were carried out using the Perdew-Burke-Ernzerhof Generalized Gradient Approximation (PBE-GGA). For electronic properties, we adopted the Tran-Blaha-modified Becke-Johnson (TB-mBJ) function. According to phonon properties, cohesiveness, and formation energy, these alloys have strong thermodynamic stability and could be produced and synthesized experimentally in a laboratory. The structural parameters are in good agreement with the available results for all compounds. From the electronic properties, HfSi₃O₈ has a small direct band gap in the Γ_V- Γ_C direction via GGA approximation, equal to 1.541 eV, indicating that the HfSi₃O₈ material is one of the future-efficient materials for the solar cell fabrication process. However, HfSiO₄ and Hf₃SiO₈ exhibit a large indirect band gap in the Γ_V-M_C direction, equal to 5.328 eV and 4.284 eV, using GGA approximation, respectively. Motivated by the prospect of using its interesting electronic structure for optoelectronic semiconductor applications, the optical properties of HfSi₃O₈, HfSiO₄, and Hf₃SiO₈ were studied. This numerical research highlights this material as the first of its kind in terms of optical properties. Given the scarcity of theoretical and experimental data, the current study may be useful for future research on these compounds. Our findings can thus pave the way for further research into the potential use of these oxide compounds in a variety of chemical, physical, and electrical applications aimed at meeting socioeconomic requirements.