Structural, Thermoelectric, Electronic, and Magnetic Properties of Pristine Intermetallic Rare-Earth-Based XMn₂Si₂ (X=Dy, Er) Compounds

Detailed Structural, thermoelectric, electronic and magnetic properties of the ternary rare-Earth based XMn2Si2 (X=Dy, Er) Compounds, are investigated using the full-potential linearized augmented-plane wave (FP-LAPW) method with generalized gradient approximation (GGA+U) in ferromagnetic phase. The basic calculations of optimization are found with the support of (PBE-GGA) to realize theoretical consistency with existing experimental consequences, although for the enhancement of magneto-electronic part the (GGA+U) technique is employed. We have identified theoretically that the ferromagnetic is the most suitable phase among three studied phases for these compounds agree well with previous experimental works. The electronic band structure indicates that these compounds are metallic through both spin channels in the FM phase. A secure hybridization occurs between the elements Dy/Er-f and Mn-d states in the valence band and the Si-p state in the conduction band. The total magnetic moments verify that the rare-Earth based DyMn2Si2 ternary inter-metallic compound showcases stronger ferromagnetic behavior patterns than the ErMn2Si2 compound. We estimated the Seebeck coefficient S, electrical and thermal conductivities, and the ZT in this study over the temperature range of 0 to 800 K. The ErMn2Si2 is a viable contender for high-temperature applications in waste heat management because of its high ZT values in the high-temperature region in thermoelectric devices.