Phase diagrams for surface alloys
Phase diagrams for surface alloys
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DOI：
10.1103/physrevb.56.5822
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发表时间：
1997-09-01
影响因子：
3.7
通讯作者：
Besenbacher, F
中科院分区：
文献类型：
--
作者：
Christensen, A;Ruban, AV;Besenbacher, F
我们讨论表面合金相和它们的稳定性的基础上构建的表面相图从表面能作为表面组成的函数。我们表明，在最简单的情况下，赝晶覆盖层有四个通用类的系统，其特征在于从散装的热隔离的迹象和迹象的表面（表面混合能）的原子之间的多余的相互作用。我们还考虑了更复杂的情况下，有序的表面相，nonpseudomorphic overlayers，第二层偏析，和多层。讨论是基于密度泛函计算使用相干势近似和有效介质理论。我们给出了自洽的密度泛函结果的偏析能和表面混合能的过渡金属和贵金属的所有组合。最后结合已有的实验结果，详细讨论了Ag/Cu（100），Pt/Cu（111），Ag/Pt（111），Co/Cu（111），Fe/Cu（111），Pd/Cu（110）等情况。
We discuss surface alloy phases and their stability based on surface phase diagrams constructed from the surface energy as a function of the surface composition. We show that in the simplest cases of pseudomorphic overlayers there are four generic classes of systems, characterized by the sign of the heat of segregation from the bulk and the sign of the excess interactions between the atoms in the surface (the surface mixing energy). We also consider the more complicated cases a with ordered surface phases, nonpseudomorphic overlayers, second layer segregation, and multilayers. The discussion is based on density-functional calculations using the coherent-potential approximation and on effective-medium theory. We give self-consistent density-functional results for the segregation energy and surface mixing energy for all combinations of the transition and noble metals. Finally we discuss in detail the cases Ag/Cu(100), Pt/Cu(111), Ag/Pt(111), Co/Cu(111), Fe/Cu(111), and Pd/Cu(110) in connection with available experimental results.