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采用集团模型和分立变分的 Xα方法研究 Ni原子在Si(111)顶位和三度开位吸附,以及在Si(100)四度位和桥位吸附的可能性,由体系的总能量最低确定稳定吸附位置,并在稳定吸附位讨论了Ni-Si成键特性和态密度.结果表明,只有当Si(111)表面弛豫情况下Ni原子才能沿[111]方向进入表面以下,但Ni原子也能沿[100]方向进入Si表面层.计算所得态密度与实验符合较好.比较所得的态密度和 NiSi_2/Si(111)的界面态密度表明位于表面下的Ni可能是生长NiSi_2的先兆.
By using the group model and the variational Xα method, the adsorption of Ni atoms at Si (111) top and third open positions and the adsorption at the Si (100) fourth position and bridge sites are studied. The total energy of the system is lowest The stable adsorption sites were determined and the Ni-Si bonding properties and density of states were discussed at stable adsorption sites. The results show that Ni atoms can only enter below the surface in the [111] direction only when Si (111) surface is relaxed, but Ni The atoms can also enter the Si surface layer in the direction of [100] .The calculated state density is in good agreement with the experimental results.The comparison of the state density and the interface state density of NiSi 2 / Si (111) indicates that the Ni underlying the surface may be NiSi 2 Aura