A first-principle study of optoelectronic, elastic, and thermodynamic properties of cubic perovskite FrQCl3 (Q = Be, Mg)

The material properties of the inorganic metal halide perovskite compound FrQCl3 (Q = Be, Mg) have been investigated using first-principles density functional theory. The optimized structures confirm their stability, and the negative formation enthalpy indicates their chemical resilience. The calculated indirect bandgaps for FrBeCl3 and FrMgCl3 are 2.057 and 3.799 eV using the GGA-PBE functional and 2.163 and 4.093 eV using the LDA-CAPZ functional, respectively. In addition, when employing the hybrid functional HSE06, these materials exhibit direct bandgaps of 3.66 and 5.76 eV, suggesting that FrBeCl3 acts as a semiconductor, while FrMgCl3 behaves as a wide bandgap semiconductor. The optical properties highlight their potential for various optoelectronic applications. Furthermore, the elastic properties affirm the mechanical stability of these compounds, as aspects such as hardness, flexibility, and softness are linked to a stable lattice structure and consistent interatomic separations. The profiles of Debye temperature provide further evidence of the thermodynamic stability of these materials. This investigation emphasizes the inter-relationships among structural, electronic, optical, mechanical, and thermodynamic properties. Given these insights, along with considerations of effective mass, these materials may be promising candidates for applications in nuclear medicine, medical imaging, and other optoelectronic devices.