Photoelectric Work Function of a Copper Single Crystal for the (100), (110), (111), and (112) Faces

The electron work function was measured by the Fowler method for four faces of a copper single crystal. The crystal was cleaned by repeated cycles of ion bombardment and annealing at 700^∘{}C under ultrahigh vacuum conditions. With uncertainties of δΦ=±0.03 eV, the work functions were found to be Φ₁₁₀=4.48 eV, Φ₁₁₂=4.53 eV, Φ₁₀₀=4.59 eV, and Φ₁₁₁=4.94 eV.