Examination and modification of Co structures on Ge(001)

Abstract

High-resolution scanning tunneling microscopy and spectroscopy enlighten the formation and composition of self-organized Co-induced structures on Ge(001). Dimer vacancies due to subsurface Co accumulate and lead to the formation of well-ordered embedded structures which consist of two alternating building blocks. A mismatch in the alternation leads to protrusions at both sides of the structures. The deposition of small amounts of Au changes the internal order of the embedded Co structures and results in longer elongated chains. Supported by Monte Carlo simulations, this modification of chain length is attributed to stress relief due to the insertion of Au-induced dimer vacancies in the Ge(001) surface.