Dimer Configuration of Si(001)2×1 Surface by Projected Potential Approach of Reflection High-Energy Electron Diffraction

The configuration of asymmetric dimers on the Si(001)2×1 surface was investigated at room temperature (RT) and high temperature (HT) by measurements of many-beam rocking curves of reflection high-energy electron diffraction (RHEED). We propose a novel projected potential approach for analyzing the dynamic structure of the Si(001)2×1 surface, on which high frequency flip-flop of asymmetric dimers occurs. This method is based on reciprocal lattice rods in the 0th Laue zone, which represent Fourier components of the projected crystal potential along the incident azimuth, so that the cross-sectional surface structure that is perpendicular to the incident azimuth can be investigated. It has been confirmed that this approach is effective for such dynamic surface structures with randomly flipping dimers. The asymmetric dimer configuration for the Si(001)2×1 surface at RT was determined to be fundamentally the same as that for the static Si(001)c(4×2) surface. The dimer relaxation into a symmetric configuration was confirmed to occur at a HT of approximately 1000 K. [DOI: 10.1380/ejssnt.2014.380]