The theory of the electron-impact ionization or (e,2e) reaction in a crystal is discussed. We consider particularly the case of fast incident electrons and small momentum transfer. Dynamical diffraction of the incident electrons plays an important role in the angular distributions of the ejected electrons. The results obtained here are contrasted with (e,2e) on free atoms.

• Received 4 January 1988

DOI:https://doi.org/10.1103/PhysRevB.38.2232