Localized theory of adsorbate-induced surface stress: Application to the LiÕMo„110... system

We present an experimental and theoretical study of surface stress in the Li/Mo~110! system, which exhibits anisotropic behavior and nonlinear coverage dependence. At low coverages the induced stress is tensile and larger in the @1̄10# direction than in @001#. With increasing coverage ~u.0.25! both stress components switch over and become compressive. With the aid of electronic structure calculations we conclude that the anisotropy is due to the atomic arrangement characteristic of the bcc ~110! surface and that the nonlinear coverage dependence is due to the combined effect of adsorbate-substrate interactions and nonlinear screening in the surface.