STM observation of restructured Cu(001) surfaces induced by Li deposition

We have studied the (2 × 1), (3 × 3) and (4 × 4) structures formed on Cu(001) with increasing Li coverage at 300 K using scanning tunneling microscope (STM). The STM images of the three phases support the previously determined structures by low-energy electron diffraction analysis. Details of the STM images of the (4 × 4) structure are discussed on the basis of the determined structure. A cluster of four Li adatoms on a small island of nine Cu atoms is observed as a single protrusion and the protrusions form the (4 × 4) lattice. We found migration of vacancies and domain boundaries. On the whole, however, the (4 × 4) structure is stable at 300 K on terraces.