Photoelectron holographic studies of As/Si(100) with sub-angstrom resolution

The atomic structure of As-terminated Si(100) has been studied using the technique of derivative photoeletron holography. The resulting holographic images clearly resolve a 0.5-Å shift from the (1 × 1) geometry 1 each As atom as a result of dimerization. Detecting this shift requires a sub-angstrom resolution that has be difficult to achieve using photoelectron holography. The improvement in resolution can be attributed to a highly anisotropic electron-scattering factor resulting in an emission beacon that helps define the atomic images.