  Using electron diffraction, we show that free electron metals such as sodium
and potassium form a highly regular quasiperiodic monolayer on the fivefold
surface of icosahedral Al-Pd-Mn and that the quasiperiodicity propagates up to
the second layer in sodium. Our photoelectron spectroscopy results show that
the quasicrystalline alkali metal adlayer does not exhibit a pseudogap near the
Fermi level, thought to be charactersitic for the electronic structure of
quasicrystalline materials. Calculations based on density functional theory
provide a model structure for the quasicrystalline alkali metal monolayer and
confirm the absence of a pseudogap.
