First-principles study on the stability and mechanical property of eta M3W3C (M=Fe, Co, Ni) compounds

The ground state properties of eta M3W3C (M=Fe, Co, Ni) compounds are discussed in this paper. The characteristics of chemical bonding and full set of elastic constants were calculated by first-principles calculations. The calculated formation enthalpy values indicate that they are thermodynamically stable structures. The Fermi surface is dominated by d bands of W and M, and the whole structures have metallic nature. The calculated bulk modulus values range from 338.6 to 376.9 GPa, larger than Fe3C, Fe2B, and Cr7C3. The population analysis reveals the attractive interactions for M3W3C are dispersed in the whole crystals.