Electron reflectivity measurements of Ag adatom concentrations on W(1 1 0)

The density of two-dimensional Ag adatom gases on W(1 1 0) is determined by monitoring local electron reflectivity using low-energy electron microscopy (LEEM). This method of adatom concentration measurement can detect changes in adatom density at least as small as 10−3 ML for a μm size region of the surface. Using this technique at high temperatures we measure the sublimation rates of Ag adatoms on W(1 1 0). At lower temperatures, where Ag adatoms condense into monolayer islands, we determine the temperature dependence of the density of adatoms coexisting with this condensed phase and compare it with previous estimates.