Hopping domain wall induced by paired adatoms on an atomic wire: si(111)-(5 x 2)-Au.
We observed an inhomogeneous fluctuation along one-dimensional atomic wires self-assembled on a Si(111) surface using scanning tunneling microscopy. The fluctuation exhibits dynamic behavior at room temperature and is observed only in a specific geometric condition; the spacing between two neighboring adatom defects is discommensurate with the wire lattice. Upon cooling, the dynamic fluctuation freezes to show the existence of an atomic-scale dislocation or domain wall induced by such "unfavorably" paired adatoms. The microscopic characteristics of the dynamic fluctuation are explained in terms of a hopping solitonic domain wall, and a local potential for this motion imposed by the adatoms is quantified.
Institute of Physics and Applied Physics and Center for Atomic Wires and Layers, Yonsei University, Seoul 120-749, Korea.
Pil-Gyu
PG
Kang
Hojin
H
Jeong
Han Woong
HW
Yeom