Comprehensive Analysis of Structural, Electronic, Dynamic, Thermodynamic and Thermoelectric Properties of Fe2SnSe4

Abstract

Functional density theory within the framework of the FP-LAPW method based on the generalized gradient approximations, GGA(WC, PBE, PBEsol) and GGA(WC, PBE, PBEsol) +U, were used to compute the exchange-correlation potential in order to examine the crystal structure, electronic structure, density of states, and magnetic properties of Fe2SnSe4 compound characterized by its orthorhombic olivine-type structure and classified under space group Pnma
The calculations indicate that the Fe2SnSe4 compound maintains stability within the ferromagnetic configuration. The GGA(WC, PBE, PBEsol) approximations provide a more accurate description of semiconductor behavior, revealing the presence of a direct band gap. Nonetheless, the (GGA-PBEsol+U) approximation demonstrates remarkable agreement, proving to be both significant and effective in forecasting the magnetic moments of the examined compound, while also yielding a lattice constant that is very close to the experimental value. In this approach, the significant Coulomb repulsion between localized d states of Fe is addressed by incorporating a Hubbard U parameter into the standard (GGA) approximations.
The study focuses on examining the stability of the material and analyzing its thermoelectric performance. The dynamic and thermodynamic parameters of the compound Fe₂SnSe₄ are calculated, with particular attention given to phonon dispersion, volume and compressibility modulus, specific heats at constant volume and constant pressure , Debye temperature , and entropy. Furthermore, the thermoelectric parameters such as Seebeck coefficients, electrical conductivity, thermal conductivity, and power factor are determined as functions of temperature. The computational results indicate that the Fe2SnSe4 material shows significant promise for thermoelectric applications.