Scattering of atomic beams off stepped surfaces

Abstract

Surface steps, because they are extended defects, give rise to strong diffuse scattering due to interference between the scattering off the different surface levels. We have calculated this diffuse scattering for a number of different configurations of random arrays of steps, using eikonal approximations which compare well with exact results in the case of a single step. This strong diffuse scattering is concentrated near the specular direction and its width is inversely proportional to the average separation of steps. Its shape gives information on the distribution and the degree of short-range order among the steps. The variation of the pattern with incident angle depends on the step height and also on the details of the step distribution.