抄録
Offer Organization: Japan Society for the Promotion of Science, System Name: Grants-in-Aid for Scientific Research, Category: Grant-in-Aid for Scientific Research (C), Fund Type: competitive_research_funding, Overall Grant Amount: - (direct: 3600000, indirect: 0)
1. Simulations of coalescence of a Au cluster and a Cu cluster were performed. Clusters of fcc and icosahedral structures were created. How the structure, temperature, and size of the clusters before coalescence affect the structure of the coalesced cluster was investigated. It was concluded that an isolated cluster of fcc or icosahedral structure preserves its original shape and remains in the quasi-stable state, that the process of coalescence of clusters consists of spread of Au atoms over the Cu cluster, transfer of the surface energy to the kinetic energy, and progress of alloying at the internal Au/Cu interface, and that an alloyed cluster is created if a Cu cluster and a Au cluster are of about the same size while a core-shell cluster is created if the size of a Au cluster is smaller than that of a Cu cluster.
Next, deposition of an icosahedral Cu cluster on a Cu substrate in Ar gas was simulated. The effect of Ar gas on the deposition and on the structural properties of the deposited cluster was investigated. It was concluded that clusters deposited at room temperature become epitaxial, and that since the kinetic energy of a cluster is dissipated by Ar gas, the cluster arrives at a substrate surface without damage and undergoes a nondispersive structural transformation.
2. Simulations of formation of a Co/Cu/Co multilayer were performed. A Co(0001) substrate was created, and 6ML of Cu atoms and 6ML of Co atoms with the velocities corresponding to ones in experiments were deposited on it. The quality of a created multilayer was evaluated by calculating its surface roughness and intermixing. It was concluded that Cuatoms form two-dimensional islands on a Co(0001) substrate, that the higher the incident energy of deposited atoms, the flatter the surface of the deposited atoms, that the best interface is obtained by the deposition of atoms with the energy 5eV among the energies leV, 5eV, and 10eV, and that the usage of the smaller incident energy of Co atoms deposited on a Cu film diminishes the interface roughness and intermixing.