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The structural and self-assembling characteristic of Pb heterostructures on the Cu (111) substrate in the early stage of the deposition process were investigated using a molecular dynamics simulation and density functional theory. The Pb islands formed on the Cu (111) surface were observed to diffuse actively in lateral directions following the layer-by-layer growth mode. A heptameric hexagonal island was found to be most stable under highly nonequilibrium conditions. This result can be explained by the tendency of Pb heterostructures, which have minimum surface energy, to have the maximum number of Pb–Pb bondings. In addition, the atomic binding energy, the surface diffusion coefficient prefactor, and the surface diffusion energy barrier for Pb adatoms were quantitatively calculated according to various shapes of Pb islands to determine the stability of the corresponding island. [ABSTRACT FROM AUTHOR]

Using the first-principles calculations, the change in magnetism and electronic structures during Cu nucleation in bcc Fe system was investigated. For modeling the Fe-rich bcc FeCu alloy, FexCu1-x (x≥0.75) were employed in the supercell system. Nonmagnetic Cu atoms were precipitated on the (100) plane of bcc Fe crystal, whereas the magnetized Cu atoms preferred to be precipitated on the (110) plane. Magnetization energies showed a linear decrease as the Cu concentration increased in bcc Fe. The magnetic moments of Fe atoms increased for larger concentration of Cu atoms. Electron density of states showed that the enhanced magnetic moment of Fe atoms resulted from the shift of minority spin states toward higher levels, which was associated with the bond formation between Cu and Fe atoms. [ABSTRACT FROM AUTHOR]

Using molecular dynamics simulation, the effect of Pb surfactant for the thin film growth of Co atoms on Cu(111) substrate was investigated. Specifically, the behavior of Co atoms being deposited on Cu(111) substrate with predeposited Pb layer was extensively investigated and compared with the case of without Pb layer to explain the effect of Pb surfactant. It was observed that Pb layer was floating during the Co deposition. It was, quantitatively, found that Pb surfactant played an important role in suppression of active diffusion of Co atoms, which was accomplished by the increase in the surface diffusion barrier energy. The energy change in the deposited Co adatom on the Cu(111) substrate with predeposited Pb layer showed that the approaching Co adatom penetrated into the Pb layer; then, the Co adatom settled down on the Cu(111) substrate. Consequently, Pb atoms around Co adatom suppressed the further diffusion of Co adatom. [ABSTRACT FROM AUTHOR]