Study of the Stability, Mechanical, Thermal, Thermoelectric, Electronic and Magnetic Properties of Full Heusler Co2XSn (X = Ti, V): using DFT Approximation

Abstract

Structural, electronic, magnetic, thermodynamic, thermal and elastic characteristics of the full-Heusler compounds Co₂XSn (X = Ti, V) have been investigated using the full-potential linearized augmented plane wave (FP-LAPW) method, which is based on density functional theory (DFT) within the wien2k code. The exchange–correlation effects were treated using the generalized gradient approximation (GGA) and GGA + U. Structural optimizations confirmed that the equilibrium lattice parameters are in harmony with the existing experimental data. The calculated formation energies and elastic parameters demonstrate the stability of these alloys. It was also observed that the studied compounds exhibit a ductile structure and anisotropic behavior. The band structure and density of states calculations reveal that the majority spin bands exhibit metallic behavior, while the minority spin bands are semiconducting with band gap for Co₂TiSn and Co₂VSn. These materials exhibit half-metallic behavior with a magnetic moment of 2 μ_B and 3 μ_B for Co₂TiSn and Co₂VSn respectively, in accordance with the Slater-Pauling rule and showing 100% spin polarization. Furthermore, their Curie temperatures (T_c) were estimated at 384.82 K (GGA-PBE) and 385.18 K (GGA + U) for Co₂TiSn, in good agreement with experimental data, while for Co₂VSn, a theoretical value of 566 K was obtained in the absence of an experimental reference. The transport properties, including electrical and thermal conductivity, the Seebeck coefficient, and the Figure of merit have been investigated to evaluate their thermoelectric response. Additionally, key thermodynamic parameters, such as the Debye temperature, thermal expansion coefficient and specific heat were calculated. These results highlight the potential of these compounds for spintronic and thermoelectric applications, demonstrating their promising multifunctional properties beyond existing studies.