Mg-X (X = Ni, Pd, Ti, Nb) interface and atomic mixture effect: a first-principles study

The structure stabilities and electronic properties of Mg-X (X = Ni, Pd, Ti, Nb) interfaces are studied by first-principles calculations, including the atomic mixture effect. In particular, the Mg-X interface structures are systemically investigated by minimizing the lattice mismatch, including the lattice constants, cell area, and included angle of the lattice (cell shape). It is found that the optimal interface matches are 4:7, 3:4, 7:8, 9:4 in surface cell atom numbers (limited up to 10 in consideration of computational cost) for Mg-Ni, Mg-Pd, Mg-Ti, Mg-Nb, and the corresponding interface energies are -0.01, -0.9, 0.4, 0.9 Jm(-2), respectively. We find that atomic mixing at the interface affects the strain, and even stablize the interfaces in the large-mismatch cases. Furthermore, exemplified with the Mg-Pd interface, we find the atoms at the interface can be exchanged under practical condition with assitance of vacancies at the interface.