Sodium and potassium monolayers on Be(0001) investigated by photoemission and electronic structure calculations
Photoemission spectra show that Be(0001) surface states shift to lower energy with increasing Na or K coverage in the monolayer range. At an intermediate monolayer coverage a quantum well state appears near the Fermi edge and shifts to lower energy reaching saturation energy at full monolayer coverage. At full monolayer coverage low energy electron diffraction shows 2 X 2 order for K while Na form