The structural, electronic, magnetic and optical characteristics of Rb₂CuCrCl₆ and Rb₂CuCrBr₆ double halide perovskites have been comprehensively investigated through first-principles density functional theory calculations. Structural optimization, combined with negative formation energies, confirms that these materials crystallize in a cubic structure and are thermodynamically stable. Their ferromagnetic ground state is established through energy-volume optimization, which yields lower total energy for the ferromagnetic configuration, and is further supported by the calculated total and partial magnetic moments. The analysis reveals that the 3d electron states of Cr are essential to the ferromagnetism, and that exchange splitting significantly enhances the net magnetic moment. Examination of the energy bands and total and partial density of states helps to explain their electronic characteristics. According to the electronic band structure analysis, both compounds exhibit indirect band-gap semiconductor behavior, with Eg values of 0.88 eV for Rb₂CuCrCl₆ and 0.79 eV for Rb₂CuCrBr₆, respectively. Furthermore, the calculated optical spectra demonstrate significant absorption from the near-infrared to the ultraviolet regions. This study presents encouraging findings that demonstrate the materials' potential for use in spintronics and optoelectronics applications.
Bensehil et al. (Sun,) studied this question.