Dynamics of Transformation of Small FCC Crystal into Icosahedral Nanoparticles

Authors V. Beloshapka1, A. Melnick2, V. Soolshenko2, D. Pimenov1

1Berdyansk State Pedagogical University, 4, Schmidt St., 71100 Berdyansk, Ukraine

2G.V. Kurdyumov Institute for Metal Physics, N.A.S. of Ukraine, 36, Academician Vernadsky Blvd., 03142 Kyiv, Ukraine

Issue Volume 13, Year 2021, Number 5
Dates Received 16 July 2021; revised manuscript received 20 October 2021; published online 25 October 2021
Citation V. Beloshapka, A. Melnick, V. Soolshenko, D. Pimenov, J. Nano- Electron. Phys. 13 No 5, 05021 (2021)
DOI https://doi.org/10.21272/jnep.13(5).05021
PACS Number(s) 61.46.Df
Keywords Instability, Icosahedral structure, Surface energy, Size effect (6) , Structure transformation.

The temperature stability of nanoparticles of such FCC metals as Ni, Cu, Au, Ag, Pt, Pd, Al, Pb was studied by the molecular dynamics method using EAM potentials. It was established that small-size particles of all the above-mentioned metals with an FCC structure are unstable and transform into Icosahedral (Ic) structures. During the FCC – Ic transformation, an abrupt decrease in potential energy was observed in the temperature dependence of the potential energy. After this transformation, the formed Ic structures remained stable in the entire temperature range up to melting. The data on the temperature and value of the potential energy jump dE during the transformation of structures with different numbers of atoms for the metals studied were calculated. The surface free energy of the structures was determined before the transformation. In addition, the potential energy distributions of atoms were found immediately before and after the transformation. The loss of stability with a decrease in the size of a nanoparticle is due to an increase in its specific surface free energy. The transformation of structures was accompanied by a decrease in the surface free energy of nanoparticles, which exceeds the increase in the volume elastic energy. The structure transformation mechanism was studied. The transformation of the structure is realized by deformation and rotation of tetrahedra, into which the FCC cluster can be divided. For all metals studied, the structure transformation mechanism is universal and is of collective and diffusionless nature. The duration of structure transformation for all structures studied did not exceed 10 – 10 of a second.

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