Patel, J. R.Freeland, P. E.Golovchenko, JeneKortan, A. R.Chadi, D. J.Qian, Guo -Xin2016-11-181986Patel, J. R., P. E. Freeland, J. A. Golovchenko, A. R. Kortan, D. J. Chadi, and Guo -Xin Qian. 1986. Normal Displacements on a Reconstructed Silicon (111) Surface: An X-Ray-Standing-Wave Study. Physical Review Letters 57, no. 24: 3077-3080. doi:10.1103/physrevlett.57.3077.0031-9007http://nrs.harvard.edu/urn-3:HUL.InstRepos:29407042The average relaxation of the top layers of a germanium-atom-tagged Si(111) surface has been measured by x-ray interferometric and fluorescence methods. The results indicate a slight outward displacement (∼2%) of the outer layers on a (5 × 5) reconstructed surface relative to a perfectly terminated silicon crystal surface. The results are in good quantitative agreement with atom positions predicted from a tight-binding-based energy-minimization calculation of the dimer-adatom stacking-fault model of the Si(111) (7 × 7) or (5 × 5) surface.en-USJournal Article2016-11-1810.1103/PhysRevLett.57.3077