Directional dependence of the surface diffusion of potassium on tungsten (112)

Abstract The diffusion constant for the system K/W(112) was determined at extremely low surface coverages using a surface ionization ion microscope. The diffusion of potassium is highly anisotropic. For the clean surface the diffusion constants parallel and perpendicular to the [111]-direction (direction of the “channels”) are given by D ∥ = 0.3 cm 2 s −1 exp (−0.46 eV / kT ) and D ⊥ = 0.3 cm 2 s −1 exp (−0.76 eV / kT ).