Surface Electronic Structure of Si(100)2×1 Studied with Angle-Resolved Photoemission

Abstract

The reconstructed Si(100)2×1 surface has been studied by a vast number of experimental and theoretical techniques in order to determine the atomic structure. The surface reconstruction is now widely believed to consist of dimers of Siatoms (symmetric or asymmetric) in the surface layer. The electronic structure of the symmetric dimer model was first calculated by APPELBAUM et al. [1]. It was, however, found to be inconsistent with angle-resolved photoemission data by HIMPSEL and EASTMAN [2] since the model resulted in metallic surface bands while the photoemission experiment showed semi conducting surface bands. This problem was solved by CHADI [3] who found that tilted (asymmetric) dimers not only gave a semi conducting surface band structure but also had a lower total energy than the symmetric dimers. This model could also explain the reports of c(4×2) and 2×2 reconstruction elements on the surface from some Low Energy Electron Diffraction (LEED) [4-7] and He diffraction [8] studies. The most direct information about the geometric structure comes from Scanning Tunneling Microscopy (STM) studies /9/. These studies showed the existence of dimers, symmetric as well as asymmetric, with a fairly large amount of defects on the surface. Besides the dominating 2×l reconstruction, regions of 2×2 and c(4×2) periodicity were also observed.KeywordsPhotoemission SpectrumSurface BandLight Incidence AnglePhotoemission ExperimentSurface Electronic StructureThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.