Analytical bond-order potential for silver, palladium, ruthenium and iodine bulk diffusion in silicon carbide

Abstract

The analytical bond-order potential has been developed for simulating fission product (Ag, Pd, Ru, and I) behavior in SiC, especially for their diffusion. We have proposed adding experimentally available elastic constants and physical properties of the elements as well as important defect formation energies calculated from density functional theory simulation to the list of typical properties as the extensive fitting database. The results from molecular dynamics simulations are in a reasonable agreement with defect properties and energy barriers of their experimental/computational counterparts. The successful validation of the new potential has established a good reliability and transferability of the potentials, which enables the ability of simulation in extended scale. The kinetic behavior such as diffusion of different interstitials is then realized by applying the new interatomic potentials. The bulk diffusion is less likely to dominate the transport of the four fission products under pure thermal condition, when we refer to their extremely small values of the effective diffusion coefficients. The interstitial mechanism is hard for Pd, Ru, and I to access due to the high formation energy and high migration energy. However, it is found that the migration energy of silver is relatively low, which indicates Ag diffusion via an interstitial mechanism being feasible, especially under irradiation condition, where massive interstitials can be formed in high-temperature nuclear reactors.

Remarkable enhancement in catechol sensing by the decoration of selective transition metals in biphenylene sheet: A systematic first-principles study

“…The diffusion barrier of 1.04 eV is found for the Pd atom on the graphyne surface [58]. The energy barrier of 1.90 eV for diffusion of the Pd atom is reported by Chen et al [59]. Our calculated energy barriers are comparable with these previous reports and large enough to restrict the clustering me metal adatoms.…”

Atomistic and mesoscale simulations to determine effective diffusion coefficient of fission products in SiC

“…The expressions of the effective Ag diffusivity in SiC provided in Eqs. (19) and (20) have been implemented in Bison in an attempt to predict the Ag release fraction measured in AGR-1 [28]. Different microstructure values were provided for different compacts, as they contain different fuel variants.…”

“…We have performed classical MD simulations in the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) [19] to predict the average diffusivity of Ag atoms along GBs in polycrystalline SiC over a wide temperature range from 2000 K to 3000 K. The analytical bond-order potential (ABOP) developed by Chen et al [20] was employed to describe the interactions between silver and silicon carbide. Using the Voronoi tessellation method, we have constructed two periodic simulation cells for two-dimensional (2-D) and three-dimensional (3-D) SiC polycrystals, respectively (see Fig.…”

Training dependency of neural network interatomic potential for molecular dynamics simulation of Ru-Si-O mixed system

“…Interface Dataset (II) further includes the data points reflecting those of Ru and SiO 2 -slab models as surface structures which are non-interface structures. We also prepared interface test sets including the data points of the SiO 2 /Ru/SiO 2 stacking structures with Ru[0001]/SiO 2 and Ru [11][12][13][14][15][16][17][18][19][20]/SiO 2 interfaces. Each interface test set includes 33 data points.…”

“…14) The first step in performing MD simulations is to develop interatomic potential. Empirical interatomic potentials for interconnect metals have already been developed in terms of Finnis-Sinclair (FS) type potential for Ru, 15) embedded atom method (EAM) type potential for Ru, 16) modified EAM (MEAM) type potential for Ru, 17) analytical bond-order potential for several covalent materials with Ru, 18) and charge-optimized many-body potential for the Cu/a-SiO 2 interface. 19) However, these empirical interatomic potentials may not adequately represent Ru/ILD interfaces with interlayers, due to their poor adaptability caused by the significant costs of parametrizing potential parameters for multi-element mixed systems.…”