Adsorption of potassium on Co(0001)

The structures of potassium overlayers on Co(0001) surface at several coverages and temperatures have been studied using work function measurements, XPS, TDS and LEED. A tentative structural phase diagram was constructed. In the coverage range from 0.17 ML to 0.31 ML a (2×2) structure was seen. Splitting of the (2×2) LEED beams was observed above 0.31 ML suggesting formation of rotated domains in the potassium layer. The rotated structure occured in an abrupt manner at the onset of the second potassium layer formation. The effects of adsorbate-adsorbate and adsorbate-substrate interactions to the structural and electronic properties of the K/Co(0001) system are discussed.