We have studied the aggregation of particles on a hetero-substrate consisting of two different substrates A and B with finite surface barriers EAB and EBA between the AB and BA boundaries, respectively. With the diffu...We have studied the aggregation of particles on a hetero-substrate consisting of two different substrates A and B with finite surface barriers EAB and EBA between the AB and BA boundaries, respectively. With the diffusion energy limited aggregation （DELA） model, we find that the number of clusters and the mean radius of gyration of the clusters are dependent on the surface barriers EAB and EBA. For the case with a constant of EBA, a series of minima are summarized as EAB ： （E0 - kBAEBA）/kAB with kAB and kBA being two integers, for main minima （kBA = kAB = 1） and two local minima （kBA = kAB and kBA = kAB ＋ 1） between two neighbouring main minima.展开更多
A lattice Kinetic Monte Carlo(KMC)approach is considered to study the statistical properties of the diffusion of Pt atom clusters on a Pt(111)surface.The interatomic potential experienced by the diffusing atoms is cal...A lattice Kinetic Monte Carlo(KMC)approach is considered to study the statistical properties of the diffusion of Pt atom clusters on a Pt(111)surface.The interatomic potential experienced by the diffusing atoms is calculated by the embedded atom method and the hopping barrier for the allowed atomic movements are calculated using the Nudged Elastic Band method.The diffusion coefficient is computed for various cluster sizes and system temperatures.The obtained results are in agreement with the ones obtained in previous experimental and theoretical works.A simple scaling argument is proposed for the size dependence of the diffusion coefficient’s prefactor.A detailed statistical analysis of the event by event KMC dynamics reveals two important and co-existing mechanisms for the diffusion of the cluster’s center of mass.At low temperatures(below T=400K)the dominating mechanism responsible for the displacement of the cluster’s center of mass is the periphery(or edge)diffusion of the atoms.At high temperatures(above T=800K)the dissociation and recombination of the clusters becomes more and more important.展开更多
基金supported by the Natural Science Foundation of Zhejiang province,China(Grant No Y607142)by the National Natural Science Foundation of China(Grant No 20771092)
文摘We have studied the aggregation of particles on a hetero-substrate consisting of two different substrates A and B with finite surface barriers EAB and EBA between the AB and BA boundaries, respectively. With the diffusion energy limited aggregation （DELA） model, we find that the number of clusters and the mean radius of gyration of the clusters are dependent on the surface barriers EAB and EBA. For the case with a constant of EBA, a series of minima are summarized as EAB ： （E0 - kBAEBA）/kAB with kAB and kBA being two integers, for main minima （kBA = kAB = 1） and two local minima （kBA = kAB and kBA = kAB ＋ 1） between two neighbouring main minima.
基金Work supported by contract nr.PNII/ID/PCCE:312/2008.
文摘A lattice Kinetic Monte Carlo(KMC)approach is considered to study the statistical properties of the diffusion of Pt atom clusters on a Pt(111)surface.The interatomic potential experienced by the diffusing atoms is calculated by the embedded atom method and the hopping barrier for the allowed atomic movements are calculated using the Nudged Elastic Band method.The diffusion coefficient is computed for various cluster sizes and system temperatures.The obtained results are in agreement with the ones obtained in previous experimental and theoretical works.A simple scaling argument is proposed for the size dependence of the diffusion coefficient’s prefactor.A detailed statistical analysis of the event by event KMC dynamics reveals two important and co-existing mechanisms for the diffusion of the cluster’s center of mass.At low temperatures(below T=400K)the dominating mechanism responsible for the displacement of the cluster’s center of mass is the periphery(or edge)diffusion of the atoms.At high temperatures(above T=800K)the dissociation and recombination of the clusters becomes more and more important.
