The effect of the composition and pressure on the phase stability and electronic, magnetic, and elastic properties of M2AX (M = Mn, Fe; A = Al, Ga, Si, Ge; X = C, N) phases

Abstract

The magnetic properties of M₂AX (M = Mn, Fe; A = Al, Ga, Si, Ge; X = C, N) phases were studied within DFT-GGA. The magnetic electronic ground state is determined. The investigation of the phase stability of M₂AX phases is performed by comparing the total energy of MAX phases to that of the set of competitive phases for calculation of the phase formation enthalpy. As the result of such an approach, we have found one stable compound (Mn₂GaC), and seven metastable ones. It is shown that several metastable MAX phases (Mn₂AlC, Fe₂GaC, Mn₂GeC, and Mn₂GeN) become stable at a small applied pressure (1.5–7 GPa). The mechanical, electronic and elastic properties of metastable MAX phases are studied.