Electron diffraction

Electron diffraction is the scattering of electrons by matter into interference patterns. The patterns demonstrate electron wave behavior and reveal atomic-scale structure.

de Broglie wavelength: The wavelength associated with a particle’s momentum, given by Planck’s constant divided by momentum. It sets the scale of electron interference and changes with electron momentum.
Selected area electron diffraction: A transmission electron microscopy method that collects a diffraction pattern from a selected specimen region. It identifies crystal phases and orientations in localized areas.
Davisson–Germer experiment: A 1927 experiment in which electrons scattered from nickel produced intensity peaks consistent with diffraction. It supplied direct experimental evidence for electron wave behavior.
X-ray diffraction: A method that infers material structure from X-ray scattering and interference. X-rays and electrons probe crystals with different interaction strengths and sample sensitivities.
Bragg's law: A condition relating the angles and wavelengths of constructive scattering from regularly spaced planes. It connects diffraction-spot positions to spacings between crystal planes.
Low-energy electron diffraction: A surface-science technique that uses low-energy electrons to form diffraction patterns from ordered surfaces. Its shallow electron penetration makes surface periodicity accessible.
George Paget Thomson: A British physicist who demonstrated electron diffraction through thin metal films and shared the 1937 Nobel Prize in Physics. His independent diffraction experiments corroborated the wave nature of electrons.
Neutron diffraction: A structural method that uses neutron scattering to study atomic positions and magnetic order. Neutrons reveal magnetic structure and penetrate samples differently from electrons.
Electron scattering: The deflection of electrons through interactions with matter, including elastic and inelastic processes. Diffraction is the coherent, wave-based structure revealed within electron scattering.
Reflection high-energy electron diffraction: A surface-sensitive diffraction method that directs high-energy electrons at a crystal at grazing incidence. It monitors surface structure during thin-film growth.

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