Ab Initio Study of the Structural, Electronic, Magnetic, Mechanical and Thermodynamic Properties of Full-Heusler Mn2CoGa

The structural, electronic, magnetic and mechanical properties of the full Heusler Mn2CoGa have been systematically investigated by first-principles calculations based on density functional theory. The determined ground state structural configuration and equilibrium lattice constant are consistent with previous theoretical and experimental studies. Mn2CoGa shows metallic nature since the band structure overlaps with the Fermi energy level in both spin directions. The total magnetic moment is mainly from the two transition metal atoms and it follows the Slater-Pauling rule, M-Total = Z(Total) - 24. Several mechanical parameters at the equilibrium lattice are calculated and provided. Mn2CoGa behaves in a brittle manner from the computed elastic moduli, whereas Mn2CoGa shows very strong anisotropy, which is revealed by the calculated direction dependent Young's modulus and shear modulus. In the last section, we further examine the thermodynamic properties of Mn2CoGa by employing the quasi-harmonic Debye model and study the variation of its cell volume, thermal expansion coefficient, heat capacity, Gruneisen constant and Debye temperature under a pressure range from 0 to 5 GPa and temperature range from 0 to 1000 K. This study provides a detailed theoretical analysis of the full Heusler compound Mn2CoGa and can give helpful guidance for further relative research.