Systematic study of spin dependent electronic, mechanical, optoelectronic and thermoelectric properties of halide double perovskites K2CuCrZ6 (Z = Cl, Br): DFT-calculations

Abstract

Since spintronic devices can operate at far higher speeds, with less power consumption, and with unlimited durability, it is a developing subject that might eventually replace traditional electronics. Double perovskites have strong spin polarization ferromagnetism, which makes them ideal materials for spintronics. Density Functional Theory has been used in the current study to examine the structural, optoelectronic, magnetic, and thermoelectric characteristics of K₂CuCrCl₆ and K₂CuCrBr₆. PBE-sol is used to compute exchange correlation potential, and mBJ potential is used to measure bandgap accurately. The two materials demonstrate a cubic structure and thermodynamic stability, as demonstrated by their respective volume optimization and negative formation energy values. Materials that are ferromagnetic can be identified by their exchange constant values and spin-based energy-volume optimization. It has been noted that the primary contribution in net magnetic moment resulting from exchange splitting and the source for ferromagnetism is the 3-d states of Cr. Additionally, studies of band structure and density-of-states reveal that materials are semiconducting, having indirect bandgap values of 1.3 eV and 1.2 eV for K₂CuCrCl₆ and K₂CuCrBr₆, respectively, and substantial ultraviolet absorption in the optical spectra of the materials. In conclusion, the study of thermoelectric characteristics involves the assessment of thermal and electrical conductivities, Seebeck coefficient, power factor, and figure of merit (ZT). K₂CuCrCl₆ and K₂CuCrBr₆ both exhibit a high ZT, with values of 0.77 and 0.71, respectively. The findings of electronic and magnetic characteristics of K₂CuCrZ₆ (Z = Cl, Br) reveal that these investigated materials hold significant potential for applications in advanced technologies like spintronic and optoelectronic devices in which their stability and tunable magnetic behavior could be leveraged to develop versatile and more efficient components.