Correlation in the Al plasma excitation

The density-density correlation function in elementary excitations of the interacting electron gas is calculated from a simple model of the dynamic form factor. For the Al plasma excitation, a correlation length of is found. It is shown that the small correlation length does not contradict the surprisingly large coherence length of almost 10 nm recently found in inelastic interference experiments. The difference of nearly 2 orders of magnitude can be traced back to the long range Coulomb interaction between probe and target electrons.Received: 24 July 2003, Published online: 19 February 2004PACS: 34.80.Pa Coherence and correlation in electron scattering - 71.45.Gm Exchange, correlation, plasmons - 82.80.Pv Electron spectroscopy     

Orientation Sensitive EELS-analysis of Boron Nitride Nanometric Hollow Spheres

We present a theory for the inelastic scattering cross-section in hexagonal boron nitride. Explicitly accounting for effects of beam convergence and a finite collection aperture, we present an approach that well describes the form of the observed Boron K-edge. We use this technique to investigate the crystallographic structure of boron nitride nanometric hollow spheres.     

Observation of ionization in a crystal interferometer

We present a new interferometric setup where interference of a fast probe electron affects the ionization cross section of an atom. Interference is detected in the intensity of the inelastically scattered electrons at the Bragg scattering angle in transmission. The crystal serves both as a target for core ionization and as a beam-splitting and phase-shifting device.     

The physical significance of the mixed dynamic form factor

We show that the mixed dynamic form factor for inelastic scattering of fast electrons in crystals is closely related to the density matrix of the probe electron and to that of the scatterer. With this insight it is possible to calculate both energy filtered diffraction patterns and energy spectroscopic high-resolution images. As an example we discuss the Si-K and -L edges.