Pt-Rh二元合金系表面偏聚的分析型EAM模型计算

MONTE CARLO SIMULATION OF SURFACE SEGREGATION IN Pt-Rh ALLOYS WITH AN ANALYTIC EAM MODEL

应用分析型ＥＡＭ多体势和Ｍｏｎｔｅ Ｃａｒｌｏ模拟方法研究了Ｐｔ－Ｒｈ合金系的表面偏聚情况．模拟结果显示，不同Ｐｔ含量的合金以及不同的表面，最外层都富集Ｐｔ原子，次外层富集Ｒｈ原子，剖面成分呈振荡分布．（１１１）面和（１００）面的成分偏聚量差别较大：（１１１）面的Ｐｔ原子偏聚量较（１００）面小得多，且前者只有最表面３层原子发生偏聚，而后者的成分偏聚影响表面至少１０层．模拟结果与已有理论和实验结果符合得很好．

The (111) and (100) surface segregations of Pt-Rh binary alloys are studied by Monte Carlo simulation technology with a modified analytical EAM potential. The simulation results show that the two top-surfaces are enriched with Pt atoms, the sub-surfaces enriched with Rh, so appears an oscillation-like distribution concentration. The detailed oscillatory behaviors of the composition depth profiles of the (111) and (100) surfaces are quite different. The amount of segregation of Pt in the (111) surface is significantly less than that in the (100) surface. The oscillation distribution occurs in more than ten surface layers for (100), while only three surface layers for (111). The simulation results are in good agreement with other theoretical and experimental results.