Structural, elastic, electronic and magnetic properties of Mn3ZnC and Mn3GeC

We report first-principles calculations, on the structural, elastic, electronic and magnetic properties of Mn3ZnC and Mn3GeC antiperovskite. Our calculations show that these compounds are more stable in the ferromagnetic states, the estimated equilibrium lattice parameters (a and V) are in agreement with the experimental ones. From the single crystal elastic constants; we have derived the polycrystalline elastic moduli, the calculated bulk modulus of Mn3ZnC and Mn3GeC which are respectively 191 and 221 GPa. Mn3ZnC shows a weak resistance to shear deformation (54 GPa) as compared to Mn3GeC (116 GPa). Similarly to previous studies on carbides antiperovskite, these compounds are good electrical conductors. The investigation of the total and partial densities of states shows that the conductivity is assured by d electrons of the transition metal atoms. The ground state was found ferromagnetic and the magnetic moment in these compounds is mainly related to the spin polarisation of Mn d electrons. The average magnetic moment per unit formula decreases from 7.02 μB to 3.18 μB for Mn3ZnC and Mn3GeC respectively.