Hopping of Ge adatoms within unit cells of the quasi-5x5-Cu reconstruction
D.V. Gruznev, D.A. Olyanich, D.N. Chubenko, A.V. Zotov and A.A. Saranin
Si(111)"5x5"-Cu reconstruction is capable to trap Ge adatom within potential basins, located in centers of its building blocks - hexagons of Cu
2Si.
Inside the basin there are several adsorption positions separated by distance equal to 1 lattice constant of Si(111) (a
0 = 3.84 Å); trapped adatoms hop between available positions.
STM movie demonstrating hopping of Ge adatoms within hexagons of "5x5"-Cu reconstruction. Scale: 20x27 nm2, scan temperature - 242 K, Ge coverage - 0.02 ML. Video is accelerated in 80 times.
STM movie demonstrating hopping of Ge adatoms within hexagons of "5x5"-Cu reconstruction. Scale: 15x15 nm2, scan temperature - 242 K, Ge coverage - 0.03 ML. Video is accelerated in 80 times.
At room temperature, Ge adatoms may overpass the relatively high barrier along the edges of hexagons and perform a long jump on 5.55 a
0 into the neighboring hexagon.
STM movie demonstrating hopping of Ge adatoms at room temperature. Since the STM scan speed is generally smaller than speed of atomic motion, oscillating Ge atoms appear in STM images at RT as shaded regions. Notice the jump of Ge atom between neighboring cells. Scale: 4.3x4.2 nm2, scan temperature - 300 K, Ge coverage - 0.02 ML. Video is accelerated in 67 times.