Physical characteristics of ferromagnetic Cr-based LiCr2X4 (X = S, Se) spinels for spintronic and solar energy devices applications

Comprehensive physical characteristics of ferromagnetic Cr-based spinels LiCr2X4 (X = S, Se) are studied using a computational model based on density functional theory (DFT) that considers their tremendous importance in spintronics and energy storage devices. The physics of these ferromagnetic LiCr2X4 (X = S, Se) spinels was probed through computational calculations by using generalized gradient approximation (PBEsol GGA) scheme of Perdew-Burke-Ernzerhof with modified Becke-Johnson (mBJ-LDA) potential to investigate the electronic, magnetic, structural, and transport properties. Structural parameters for both spinels have been calculated after their optimization in the ferromagnetic phase. Negative formation energy and Born stability criteria were also calculated, and it was observed that these spinels have thermodynamical and structural stability. The density of states (DOS) and band structure (BS) were calculated using the mBJ-LDA potential technique required for complete analysis of the ferromagnetic nature of these spinels. The predicted band gap using mBJ-LDA represents both spinels having potential applications in solar cell devices. Study of DOS enables us to find that the prominent spin role from electrons can be revealed by negative indirect interchange energy Delta(x)(pd) values that also obey the form Delta(x)(d) > Delta E-cry. Furthermore, exchange parameters were also necessary to be calculated to assure the ferromagnetic behavior of the under studied spinels. Lastly, under the light of classical Boltzmann transport theory, the effect of spin on the different perspectives of electronic transport, Seebeck coefficient, and power factor was briefly probed.