Reflection high-energy electron diffraction: Difference between revisions

Revision as of 18:06, 20 July 2020

Revision as of 21:15, 24 August 2020

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where λ is the wavelength of incident electrons.

[[File:Ewald Spheresphere construction in Reflection high-energy electron diffraction (RHEED).gifsvg|thumbnailalt=|400pxthumb|400x400px|'''Figure 3'''. The RHEED construction of the Ewald's Spheresphere atfor theelastic samplediffraction surfacein RHEED. The radius of the Ewald's sphere is equal to the magnitude of the k0incoming electron's wave vector k_i, which isends at the reciprocalorigin of the wavelengthtwo-dimensional reciprocal lattice. The wave vector of the incidentoutgoing electrons. Theelectron k_hl vector, corresponds to an allowed diffraction condition, and the G vector is the difference between the kcomponents andparallel k₀to vectors.the Insurface this figure,of the ktwo vectorwave vectors is the specularreciprocal beamlattice vector G_hl.]]

[[File:Ewald Sphere.gif|thumbnail|400px|'''Figure 3'''. The RHEED construction of the Ewald's Sphere at the sample surface. The radius of the Ewald's sphere is equal to the magnitude of the k0 vector, which is the reciprocal of the wavelength of the incident electrons. The k vector, corresponds to an allowed diffraction condition, and the G vector is the difference between the k and k₀ vectors. In this figure, the k vector is the specular beam.]]

Diffraction conditions are satisfied where the rods of reciprocal lattice intersect the Ewald's sphere. Therefore, the magnitude of a vector from the origin of the Ewald's sphere to the intersection of any reciprocal lattice rods is equal in magnitude to that of the incident beam. Equation 2 shows this relationship.