Diffraction of He Atoms at a Si(100) Surface

Abstract

Diffraction of helium atoms at a clear Si(100) surface has been observed. Integral-order, half-order, and quarter-order peaks consistent with the two-domain $c(4\mathrm{}\times 2)$ surface reconstruction have been recorded. Additional peaks at the ($\frac{\overline{1}}{2}\frac{\overline{1}}{2}$) and ($\frac{\overline{3}}{2}\frac{\overline{3}}{2}$) positions are also seen. The diffraction intensities amount to ∼${10}^{-3\mathrm{}}$ of the incident beam. The major portion of the scattering is spread over a large range of solid angle with broad maxima characteristic of rainbow scattering.