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 (Eg) and details about the dispersion of electronic states among bands, the electronic properties have been evaluated. Cs2YHgCl6 has direct electronic gap (Eg) of 3.53 eV in spin-up and 3.59 eV in spin-down states. K2YHgCl6 also displays direct Eg 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 µB for K2YHgCl6 and 8.79854 µB 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.