Computational Exploration of Structural, Elastic, Optoelectronic and Magnetic Properties of A2YHgCl6 (A = Cs, K) Using Enhanced Computational Techniques

This research utilizes first-principle methods to explore the geometric, elastic, electronic, magnetic, and optical characteristics of A₂YHgCl₆ (A = Cs or K). To ensure precise and comprehensive insights into their physical properties, the mBJ functional is utilized. The findings confirm that A₂YHgCl₆ exhibit strong, thermodynamic, and structural stability. Both substances meet the Born stability requirements, affirming their mechanical stability under applied stress and validates their resistance to structural collapse or deformation. To figure out the band gaps (E_g) and details about the dispersion of electronic states among bands, the electronic properties have been evaluated. Cs₂YHgCl₆ has direct electronic gap (E_g) of 3.53 eV in spin-up and 3.59 eV in spin-down states. K₂YHgCl₆ also displays direct E_g of 3.30 eV in spin-down and 3.74 eV in spin-up state. These values confirm the semiconducting nature of both compounds. Magnetic features reveal the total magnetic moment value of 8.79899 µ_B for K₂YHgCl₆ and 8.79854 µ_B for Cs₂YHgCl₆. The largest optical conductivity value is computed to be 4480 1/Ωcm at 12.83 eV for K₂YHgCl₆ and 4263 1/Ωcm at 13.18 eV for Cs₂YHgCl₆. The imaginary part of dielectric ε₂(ω) shows absorption, reaches a maximum value of 2.58 at 12.80 eV for K₂YHgCl₆ and 3.21 at 6.75 eV for Cs₂YHgCl₆. The optical conduction and absorption plots exhibit maxima extending beyond the UV-VIS spectrum, suggesting these materials are well-suited for photovoltaics applications.