First-principles Study of Si-embedded Ni(100) Surfaces

抄録

First-principles total-energy calculations were applied to 0 to 1 ML of silicon-embedded Ni(100) surfaces in the outmost layer within a 2 × 4 unit cell. Up to a half monolayer of embedded silicon, the surface energy decreased monotonically with increasing the number of embedded silicon, and the lowest energy structure was a √2 × √2-R45° [or c(2 × 2)] structure with diagonally aligned embedded silicon of 0.5 ML. Beyond the half monolayer, the surface energy increased with increasing the number of embedded silicon. The energy of the silicon-embedded structure in the outmost layer of the Ni(100) surface was compared with silicon embedded in the second layer and silicon adsorbed on the Ni(100) surface. Both configurations gave higher energies, which shows the robustness of the √2 × √2-R45° structure on the Ni(100) surface. The present results are in perfect agreement with our recent report [T. Fukuda et al., Jpn. J. Appl. Phys. 59, 065501 (2020)].