First-principles investigation of structural, electronic, optical, and magnetic properties of a scintillating double perovskite halides (Cs2LiCeX6) with (X = F, Br, and I)

In this study, several physical properties (structural, electronic, magnetic, and optical) of a scintillating double perovskite halide Cs2(L)iCeX(6) (X = F, Br, and I) are investigated using the density functional theory (DFT) within the Wien2k code. The optimized lattice parameter (a(0)) of Cs2LiCeBr6 agrees perfectly with the experimental results. The optimized ground state energy appears to confirm the cubic stability. The band structure and densities of states are explored using PBE-GGA coupled with Tb-mBJ approximation. In the spin-up channel, the compound Cs2LiCeX6 (X = F, Br, and I) has a Fermi level occupied, with a band gap of 1.966 eV, 1.350 eV, and 1.184 eV, respectively. While in the spin-down channel, the double perovskite halide Cs2LiCeBr6 and Cs2LiCeI6 behave like a semiconductor, with a band gap of 3.293 eV and 2.418 eV, respectively. The asymmetric density of states in both spin channels and the optimized energy volume curve in spin-polarized calculation assert to the ferromagnetic nature. The optical properties are calculated, and it is revealed that Cs2LiCeBr6 and Cs2LiCeI6 has a high optical conductivity than Cs2LiCeF6. The absorption in the ultraviolet and gamma frequency range, along with the emittance in the visible light unlocks the door for various applications, like medical imaging, radiation detection and particle detection.