VACANCY-VACANCY INTERACTION ON GE-COVERED SI(001)

When Ge atoms are deposited onto a Si(001) substrate, dimer vacancies are created in the strained system. At sufficiently high concentrations, interactions between the vacancies cause them to line up, resulting in the (2 x n) reconstruction. By analyzing the thermal fluctuations around the ideal (2 x n) structure with scanning tunneling microscopy and using transfer matrix theory, the form of the dimer vacancy-vacancy interaction and a value for its magnitude have been determined.