Abstract:

This study investigates the structural, electronic, magnetic, thermodynamic, and thermoelectric properties of the Ru₂TiMn Heusler alloy using Density Functional Theory (DFT). The alloy undergoes a martensitic phase transformation from a cubic to a tetragonal structure, stabilizing at a c/a ratio of 0.92, as determined by the Birch-Murnaghan equation of state. The negative formation energy (-0.45 eV/atom) indicates energetic favourability and potential synthesizability under practical conditions. Electronic structure analysis shows a nonzero density of states (DOS) at the Fermi level in both spin-up and spin-down channels, confirming the metallic nature of Ru₂TiMn. Magnetic properties reveal a total magnetic moment of approximately 3.025 μB, primarily from Mn d-orbitals. Phonon dispersion calculations exhibit no imaginary frequencies, ensuring dynamical stability. Thermodynamic properties over 0–2000 K show increasing entropy with temperature, while free energy becomes more negative, indicating strong stability. Specific heat (Cₚ) varies from 0 J/mol·K at 0 K to approximately 125 J/mol·K at 2000 K. Thermoelectric analysis reveals a high Seebeck coefficient of 100 μV/K, combined with low lattice thermal conductivity of 1.25 W/m·K), and significant electrical conductivity. These attributes result in a high thermoelectric figure of merit (zT), exceeding 1.2 at elevated temperatures. This study underscores Ru₂TiMn's promise as a thermoelectric material for efficient waste heat recovery, providing a solid foundation for future experimental studies and applications.

Description:

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