Strain-induced quasi-one-dimensional rare-earth silicide structures on Si(111)

Abstract

After deposition of rare-earth elements (Dy, Tb) on Si(111) at elevated temperatures, a formerly unknown (2 root 3 x root 3) R30 degrees. reconstruction is observed by low-energy electron diffraction, while scanning tunneling microscopy measurements exhibit a (root 3 x root 3) R30 degrees. reconstruction. On the basis of density-functional theory calculations, the structure of the larger unit cell is explained by periodically arranged subsurface Si vacancies. The vacancy network in the first subsurface layer has a (root 3 x root 3) R30 degrees. periodicity, while strain is released by a (2 root 3 x root 3) R30 degrees. Si vacancy network in the second subsurface layer. In addition, this vacancy network forms quasi-one-dimensional structures (striped domains) separated by periodically arranged antiphase domain boundaries. The diffraction spot profiles are explained in detail by kinematic diffraction theory calculations, and average domain widths are deduced.