GEOMETRIES OF LI INDUCED STRUCTURES ON CU(001) - LEED AND ARUPS STUDIES

Superstructures of c(2 x 2) and (2 x 1) are formed on Cu(001) initially with increasing Li coverage at sample temperatures of 180 and 300 K, respectively, and these structures are determined by low-energy electron diffraction intensity analysis. It is found that Li adatoms are located on fourfold hollow sites for the c(2 x 2) structure and that the (2 x 1) structure is caused by a missing-row-type restructuring of the top layer of Cu(001). The Tamm-type surface state of the Cu(001) surface is monitored as a function of Li coverage at 180 and 300 K with angle-resolved ultraviolet photoelectron spectroscopy at the MBAR point. Different behaviors of the surface state at 180 and 300 K at low coverages are discussed in connection with different geometries of Li adatoms formed at the two temperatures.