Incoherent Imaging of Crystals Using Thermally Scattered Electrons

Thermal diffuse scattering of electrons through large angles by a simple low-index crystal projection is examined in the context of a phonon model, based on the Warren approximation of X-ray diffraction. The scattering from an individual atomic column is visualized in terms of an assembly of independent 'packets' of atoms. Within a packet, the scattering is partially coherent, causing the columnar intensity to deviate from that calculated with an Einstein independent oscillator model. For typical atomic spacings, this deviation is limited to within 20%.