Observation of ordered structures for S/Cu(111) at low temperature and coverage

Via scanning tunneling microscopy and low energy electron loss diffraction we observe ordered low-temperature surface structures for S/Cu(111) at low- S coverage and characterize the system also with core level photoemission. The first structure to appear upon S deposition is honeycomblike with a lar ge mesh [(root 43 x root 43) R +/- 7.5 degrees], a large nearest S-S distan ce (similar to 4 Angstrom) and low-ordering temperature (<170K). Islands of this structure are observed at low coverage (theta similar to 0.05) and at theta similar to 0.25 nearly all of the surface area is covered. [S0163-18 29(99)07139-8].