ADP potential for the Au-Rh system and its application in element segregation of nanoparticles

G Wang and YS Xu and P Qian and YJ Su, COMPUTATIONAL MATERIALS SCIENCE, 186, 110002 (2021).

DOI: 10.1016/j.commatsci.2020.110002

A new ADP potential for the Au-Rh system was developed by fitting to a database of experimental and first principle data, and the validity of the potential was tested. Then, the element segregation of Au-Rh nanoparticles was studied by Monte Carlo simulation using this potential. The results show that the preferential segregation behavior of atoms in Au-Rh nanoparticles is not affected by the particle size. On the surface, due to the large surface energy difference between Au and Rh, the element segregation is mainly induced by the surface energy, and Au atoms preferentially occupy the lower coordination sites. In the body, Au atoms tend to occupy the sites with small local pressure to release strain energy, while the whole system tends to reduce the interface area to decrease the interface energy. The element segregation is primarily induced by the strain energy, and the interface energy also participates in the competition. The final structure is the result of the competition between strain energy and interface energy.

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