Structure and electronic behavior of 26-atom Cu-Ag and Cu-Au nanoalloys

• Published in: The European physical journal. D, Atomic, molecular, and optical physics Atomic, molecular, and optical physics, 2016-09, Vol.70 (9), p.1-7, Article 194
• Main Authors: Guzmán-Ramírez, Gregorio, Robles, Juvencio, Aguilera-Granja, Faustino
• Format: Article
• Language: English
• Subjects: Applications of Nonlinear Dynamics and Chaos Theory; Atomic; Clusters; Copper base alloys; Core-shell structure; Density functional theory; Gold; Interatomic distance; Intermetallic compounds; Molecular; Nanoalloys; Optical and Plasma Physics; Organic chemistry; Physical Chemistry; Physics; Physics and Astronomy; Quantum Information Technology; Quantum Physics; Regular Article; Silver; Spectroscopy/Spectrometry; Spintronics
• ISSN: 1434-6060; 1434-6079
• DOI: 10.1140/epjd/e2016-70021-1

We hereby present a density functional theory (DFT) study of the structural, energetic, and electronic properties of the binary clusters Cu n X 26- n (with X = Ag and Au). Our electronic calculations were performed with the DFT package GAUSSIAN 09, and we chose the BPW91 exchange correlation functional in combination with an effective core potential LANL2DZ basis set as our level of theory. We find that in the case of these clusters and in a completely different way – as compared to the bulk chemical order observed in both alloys CuAg (segregation) and CuAu (ordering) –, for small n both Ag and Au clusters exhibit a similar chemical order, finding the Cu atoms in the center of the cluster with the tendency to form core shell structures. On the other hand, for large n values the Ag and Au atoms tend to occupy surface positions forming separated surface islands that keep the two metal atoms separated as long as the concentration allows it. Concerning the structural properties, a clear increase in the interatomic distance of the Ag-Ag and Au-Au surface pairs is observed, particularly in the equiatomic region. In conclusion, both nanoalloys CuAg and CuAu behave quite similarly in contrast to their respective bulk cases. Graphical abstract