OBSERVATIONS OF COVERAGE-DEPENDENT AND TEMPERATURE-DEPENDENT SURFACE-STRUCTURES FORMED UPON LI DEPOSITION ON CU(110)

A systematic study of surface structures of Li-covered Cu(110) was per formed by means of low-energy electron-diffraction (LEED) and Auger el ectron spectroscopy techniques. The experiments were carried out with increasing deposition of Li both at low temperature (90 K) and room te mperature (300 K). At 90 K a series of LEED patterns, (3 X 1), (2 X 1) , (3 X 1), and successive complicated structures were observed with in creasing Li coverage. The sequence of the LEED patterns was interprete d as simple overlayer structures of Li in terms of a continuous increa se of the packing density of deposited Li atoms sitting in the trough along the [110BAR] direction of the Cu(110) surface. Marked difference s in the sequence of the LEED structures were observed for observation s at 300 K; the sequence of the structures was (1 X 2), (1 X 1), (4 X 1), (5 X 1), and (n X 1) where n < 8 with an increase of Li coverage. The first (1 X 2) structure was assigned to a missing-row-type restruc turing of the substrate Cu atoms. The structure models for the (4 X 1) , (5 X 1), and so on were discussed in terms of the formation of Li-Cu surface alloys proposed previously by Tochihara and Mizuno for the Li /Cu(100) system.