Although the stable surface structure of a clean, thermally annealed Si(111) is a (7 × 7) at room temperature, a metastable (1 × 1) structure can be obtained by irradiating the crystal with the output of a pulsed ruby laser. The structural determination of this atomically clean (1 × 1) arrangement is important since it may subsequently be used as a basis for the eventual understanding of the (7 × 7) reconstruction. A LEED analysis of the (1 × 1) structure is reported in which I–V profile data for the six lowest indexed nonspecular beams have been collected with the incident electron beam normal to the surface. These experimental profiles have been compared with the results of dynamical calculations, in which the first and second interlayer spacings of the truncated bulk model were varied. Also, nonstructural parameters have been varied in the calculations. The results suggest a bulklike layer termination exhibiting no ordered lateral reconstruction with the first interlayer spacing contracted by 25.5±2.5% and the second expanded by 3.2±1.5% with respect to bulk values. The best comparison between calculated and experimental I–V profiles has produced a six-beam Zanazzi and Jona R-factor of 0.115.

Zehner, D. M., Noonan, J. R., Davis, H. L., & White, C. W. (1981). Atomic structure of laser annealed Si(111)–(1×1). Journal of Vacuum Science and Technology, 18(3), 852–855.