Atomic processes in vacancy island motion on Ag(111)

Kürpick, Ulrike; Kürpick, P.; Rahman, Talat S.

doi:10.1016/s0039-6028(97)00140-4

Cited by 34 publications

(35 citation statements)

References 19 publications

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“…The inset shows the minimum of the curves magnified for better comparison. 27.2meV/Å for 393K for the line tension (i.e., the average of that of A and B-type steps, since we neglect their difference in the simulations).…”

Section: Resultsmentioning

confidence: 99%

“…These higher energy barriers for higher T may be an indication of different regions of transport mechanisms on Pb(111). The downward bend at higher temperatures might be an indication of other transport mechanisms setting in that are excluded in our MC algorithm, such as concerted moves of dimers or other multi-mers, 27 or one might think of corner rounding 29,30 having a significant effect, but not included in our MC as it requires next nearest neighbor hops.…”

Section: Discussion and Summarymentioning

confidence: 99%

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Correlations in nanoscale step fluctuations: Comparison of simulation and experiments

et al. 2006

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We analyze correlations in step-edge fluctuations using the Bortz-Kalos-Lebowitz kinetic Monte Carlo algorithm, with a 2-parameter expression for energy barriers, and compare with our VT-STM line-scan experiments on spiral steps on Pb(111). The scaling of the correlation times gives a dynamic exponent confirming the expected step-edge-diffusion rate-limiting kinetics both in the MC and in the experiments. We both calculate and measure the temperature dependence of (mass) transport properties via the characteristic hopping times and deduce therefrom the notoriouslyelusive effective energy barrier for the edge fluctuations. With a careful analysis we point out the necessity of a more complex model to mimic the kinetics of a Pb(111) surface for certain parameter ranges.

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Section: Resultsmentioning

confidence: 99%

Section: Discussion and Summarymentioning

confidence: 99%

Correlations in nanoscale step fluctuations: Comparison of simulation and experiments

et al. 2006

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“…Since these dependencies are not unequivocally extracted from experimental data, because of the large error bars involved, the issue is not yet completely settled, although the bias is towards periphery diffusion. Molecular dynamics simulations of Ag vacancy island on Ag(111) [30], on the other hand, have shown a preference for periphery diffusion , while in the case of the elasticcontinuum models the three mechanisms lead to characteristic decays of the time and space correlation functions. Several questions about the elastic-continuum based models, however, remain as shown by Bogicevic et al [31] who find that the exponents in the power law dependence of the diffusion coefficient on island size were themselves temperature dependent and material specific, unlike predictions of the simpler earlier model calculations.…”

Section: Application Of Kmc To Cluster Diffusionmentioning

confidence: 99%

Atomistic studies of thin film growth

Rahman

Gosh

Trushin³

et al. 2004

SPIE Proceedings

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We present here a summary of some recent techniques used for atomistic studies of thin film growth and morphological evolution. Specific attention is given to a new kinetic Monte Carlo technique in which the usage of unique labeling schemes of the environment of the diffusing entity allows the development of a closed data base of 49 single atom diffusion processes for periphery motion. The activation energy barriers and diffusion paths are calculated using reliable manybody interatomic potentials. The application of the technique to the diffusion of 2-dimensional Cu clusters on Cu(111) shows interesting trends in the diffusion rate and in the frequencies of the microscopic mechanisms which are responsible for the motion of the clusters, as a function of cluster size and temperature. The results are compared with those obtained from yet another novel kinetic Monte Carlo technique in which an open data base of the energetics and diffusion paths of microscopic processes is continuously updated as needed. Comparisons are made with experimental data where available.

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“…Motivated by experimental observations, initially using field ion microscopy ͑FIM͒, 1-6 and more recently with the use of the scanning tunneling microscope ͑STM͒, 7-15 the study of adatom and vacancy island diffusion as a function of size has been an important concern also for many theorists [16][17][18][19][20][21][22][23][24][25] Because of the inherent differences in the microscopic processes responsible for the diffusion and its scaling behavior with size, the discussion has naturally bifurcated into those for the larger islands, usually containing more than 20 atoms, and the smaller ones ͑N Ͻ 20͒. For the larger islands, the diffusion coefficients appear to scale as a function of the size and the scaling exponent is expected to reflect the intervening atomistic processes responsible for the diffusion.…”

Section: Introductionmentioning

confidence: 99%

Diffusion of small two-dimensional Cu islands on Cu(111) studied with a kinetic Monte Carlo method

et al. 2006

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Diffusion of small two-dimensional Cu islands ͑containing up to 10 atoms͒ on Cu͑111͒ has been studied using the newly developed self-learning Kinetic Monte Carlo ͑SLKMC͒ method which is based on a database of diffusion processes and their energetics accumulated automatically during the implementation of the SLKMC code. Results obtained from simulations in which atoms hop from one fcc hollow site to another are compared with those obtained from a parallel set of simulations in which the database is supplemented by processes revealed in complementary molecular dynamics simulations at 500 K. They include processes involving the hcp ͑stacking-fault͒ sites, which facilitate concerted motion of the islands ͑simultaneous motion of all atoms in the island͒. A significant difference in the scaling of the effective diffusion barriers with island size is observed in the two cases. In particular, the presence of concerted island motion leads to an almost linear increase in the effective diffusion barrier with size, while its absence accounts for strong size-dependent oscillations and anomalous behavior for trimers and heptamers. We also identify and discuss in detail the key microscopic processes responsible for the diffusion and examine the frequencies of their occurrence, as a function of island size and substrate temperature.

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Atomic processes in vacancy island motion on Ag(111)

Cited by 34 publications

References 19 publications

Correlations in nanoscale step fluctuations: Comparison of simulation and experiments

Correlations in nanoscale step fluctuations: Comparison of simulation and experiments

Atomistic studies of thin film growth

Diffusion of small two-dimensional Cu islands on Cu(111) studied with a kinetic Monte Carlo method

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