Self-organized two-dimensional lattice of magic clusters
M. Y. Lai and Y. L. Wang
Phys. Rev. B 64, 241404(R) (2001)

Under certain deposition conditions, gallium induces almost exclusive formation of a type of especially stable clusters—magic clusters, on the 7x7-reconstructed silicon(111) surface. The cluster has a triangular closed-shell structure and resides on the center of a 7x7 half unit-cell. As the gallium coverage is increased, the cluster density increases proportionally, leading essentially to the complete filling of the 7x7 half unit cells and the creation of an unprecedented two-dimensional lattice of magic clusters. A structure model employing three silicon atoms to link six gallium atoms into a configuration with satisfied bonding is proposed to account for the cluster’s stability.

在某些蒸鍍條件下，鎵原子在矽(111)表面的晶胞上會結聚出一種特別穩定、形狀為三角形的奇異原子團。隨著鎵的蒸鍍量增加，這種原子團數目也會成比例增加，直到鋪滿整個表面，形成一個由表面奇異原子團所鋪成的二維晶體，這是科學家第一次在表面上成長出尺寸、位置都達到原子級精準的奈米結構。我們提出這種原子團是由六顆鎵原子與原先在表面的三顆矽原子所組成，其間各原子的價電子都完全鍵結，這可以說明為何此原子團具有特別高的穩定性。