Ab-Initio Study on Adsorption and Diffusion of Au Atoms on Clean Si(001) and H-Si(001) Surface

Ju, Wei Wei; Li, Tong Wei; You, Jing Han; Tang, Zheng Xin; Gong, Xiao Yang; Wang, Hui; Zhen, Zhi Qiang; Zhang, Qing Guo

doi:10.4028/www.scientific.net/kem.368-372.1699

Cited by 2 publications

(2 citation statements)

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“…The mechanism and rate of diffusion of a Au adatom on the reconstructed Si(100)-2 × 1 surface has been calculated using the CI-NEB method for identifying optimal diffusion paths with energy and atomic forces estimated from DFT/PBEsol. While the most stable binding site is found to be in between dimer rows, in agreement with previous theoretical calculations and STM experimental measurements [16,17], the dominant diffusion mechanism is found to involve promotion of the adatom into metastable sites on top of a dimer row and multiple hops along the row, before the adatom settles down again into an optimal binding site between dimer rows. This indirect diffusion mechanism becomes more dominant the lower is the temperature.…”

Section: Discussionsupporting

confidence: 87%

“…An adatom initially sitting on top of a row was observed to move in between rows during STM manipulation, indicating that the latter site is more stable. Previous density functional theory (DFT) studies had reported binding sites in between the dimer rows (BDRs) [17] and there it was assumed that diffusion occurs by adatom hops between such binding sites, the adatom thereby remaining in between dimer rows during diffusion. More extensive DFT calculations by Chiaravalloti et al, however, identified also two binding sites on top of the dimer rows, an asymmetric site at the edge of the dimer row (TDR1) and a symmetric site in the center of a row (TDR2).…”

Section: Introductionmentioning

confidence: 99%

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Indirect mechanism of Au adatom diffusion on the Si(100) surface

et al. 2022

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Calculations of the diffusion of a Au adatom on the dimer reconstructed Si(100)-2 × 1 surface reveal an interesting mechanism that differs significantly from a direct path between optimal binding sites, which are located in between dimer rows. Instead, the active diffusion mechanism involves promotion of the adatom to higher-energy sites on top of a dimer row and then fast migration along the row, visiting ca. a hundred sites at room temperature, before falling back down into an optimal binding site. This top-of-row mechanism becomes more important the lower is the temperature. The calculations are carried out by finding minimum energy paths on the energy surface obtained from density functional theory within the PBEsol functional approximation followed by kinetic Monte Carlo simulations of the diffusion over a range of temperature from 200 to 900 K. While the activation energy for the direct diffusion mechanism, both parallel and perpendicular to the dimer rows, is calculated to be 0.84 eV, the effective activation energy for the indirect mechanism parallel to the rows is on average 0.56 eV.

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Section: Discussionsupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%