Understanding the Bi-Axial Strain Influence on Mn3Si2Te6 : A DFT Study of Electronic, Magnetic, Optical, and Thermoelectric Properties

The increasing focus on sustainable and renewable energy sources has boosted the demand for double perovskites in applications such as solar cells and thermoelectric energy converters. In the recent study, understanding the bi-axial strain influence on Mn ₃ Si ₂ Te ₆ (MST): DFT study of electronic, magnetic, optical, and thermoelectric properties were systematically analyzed by using the WIEN2K code. The electronic nature was found to be highly sensitive to external electric fields under biaxial strain engineering. Experimentally, MST show the metallic nature while in DFT study of strain engineering the material become half-semimetal at 5% tensile strain with indirect bandgap of 0.732 eV at the Γ − κ symmetry point with SCF (self-consistent field) calculation and more accurate the indirect bandgap of 1.24 eV under TB-mBJ approximation. It was observed that, the compressive strain reduces the bandgap, while tensile strain increases it. The optical property predictions indicate that MST exhibits absorption in the ultraviolet and visible regions, with a blue shift under tensile strain and a red shift under compressive strain. In the absorption coefficient of SOC (Spin orbit coupling), the black line show the maximum absorption in xx plane in between visible region of 1.6 eV to 3.2 eV. The thermoelectric performance was evaluated over the temperature range of 300-800 K of MST compound under strain engineering were investigated by BoltzTraP Code including features i.e Seebeck coefficient, electrical conductivity, thermal conductivity, power factor, and figure of merit (ZT). The Seebeck coefficient and electrical conductivity generally decrease with increasing temperature, while thermal conductivity typically increases. The thermoelectric performance was evaluated over the temperature range of 300-800 K using the figure of merit (ZT). The ZT values approached unity, and the ultralow lattice thermal conductivity enhances the significance of these double perovskites for use in thermoelectric generators. Under strain engineering of MST material, the highest value of ZT in n-type region at 0.723 while lowest value of ZT in p-type region at 0.716 by computationally anaylsis.