Structural, electronic properties and stability of AlCMn3 (1 1 1) surfaces by first-principles calculations

The directly cleaved AlMn3, terminations and constructed AlMn2, CMn terminations have been built for AlCMn3 (1 1 1) surface. The surface relaxation, cleavage and surface energies, surface grand potential along with the surface electronic structure have been calculated with the first-principles methods based on the density functional theory (DFT). Results of the relaxed structure for each termination show that the relaxation mainly occur on the uppermost two atomic layers, and larger rumpling locate at the first layer of the AlMn2 and CMn terminations. Analysis on of the surface energies and grand potential reveals that only the AlMn2 and C terminations can be formed and its stabilities depend on the range of the ΔμAl and ΔμMn. Furthermore, surface electronic calculations indicate that the Al-Mn bond is the largest bond population among the four terminations slabs and demonstrates that the outmost layer of AlCMn3 (1 1 1) surfaces have a preference of AlMn2 and C terminations.