Figure 4

Cross-sectional side view and top view of the atomic structure models of (a) 4a₀, (b) 5a₀, and (c) 8a₀ NW. Silicon atoms in silicide are large gray and bulk silicon atoms are smaller black circles, and Gd atoms are large red circles. The translucent yellow circles indicate the bright positions of the STM images. The black bars below the wire in (c) indicate the identical units of the top-most structure of the center of the wider NWs than 5a₀ as the width of the wire increases by 1a₀.