Using scanning tunnelling microscopy, we demonstrate the nucleation density of Fe islands on surface of nanoscale Pb films oscillates with film thickness, providing a direct manifestation of quantum size effect on surface diffusion. The Fe adatom diffusion barriers were derived to be 204 and 187 meV on a 21 and 26 monolayer (ML) Pb film, respectively, by matching the kinetic Monte Carlo simulations to the experimental island densities. The effect is further illustrated by growth on wedged Pb films, where the Fe island density is consistently higher on the odd-layer films than on the even-layer films in the thickness range of 11 to 15 ML.
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Authors
Jinfeng Jia
Department of Physics, Tsinghua University, Beijing 100084, China
Liying Ma
Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
Lin Tang
Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
Xucun Ma
Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
Q.K. Xue
Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
Department of Physics, Tsinghua University, Beijing 100084, China; Institute of Physics, Chinese Academy of Sciences,Beijing 100080, China
IoP, Chinese Academy of Science
Y. Han
Department of Material Science and Engineering, University of Utah, Salt Lake City, Utah 84112
Steve Huang
Department of Material Science and Engineering, University of Utah, Salt Lake City, Utah 84112
Feng Liu
Department of Material Science and Engineering, University of Utah, Salt Lake City, Utah 84112
