The fine structure of X-ray diffuse scattering in the vicinity of high-angle superlattice Bragg reflections

Abstract

Triple‐axis X‐ray diffractometry was used to study diffuse scattering from an AlAs/GaAs superlattice grown on an [001]‐oriented GaAs substrate by molecular beam epitaxy. Reciprocal‐space maps were obtained around the 002 reflection from the superlattice and its low‐angle first‐order satellite. The data obtained reveal quasi‐Bragg diffuse‐scattering sheets caused by conformal behavior of interfacial roughness as well as amplification of diffuse scattering when the incoming or outgoing angle is nearly equal to the Bragg angle of the superlattice or substrate. The observed features of diffuse‐scattering fine structure are explained within the framework of the distorted‐wave Born approximation. Nevertheless, this approximation is shown to be incorrect for quantitative analysis of diffuse scattering. In particular, the observed domination in intensity of the incoming Bragg features over the outgoing ones is shown to reflect the decay rate of the coherent X‐ray field through the diffuse‐scattering channel, which is not negligible relative to the coherent diffraction.

Decoherence phenomenon in X-ray diffraction and scattering from rough multilayers

“…Nevertheless, in the experiment we have repeatedly observed the violation of the reciprocity principle [3][4][5]. The main reason of this violation can be well illustrated by the following.…”

“…[5], we have studied the diffuse scattering from an AlAs/GaAs superlattice near the wideangle Bragg reflection and its satellite. One of the important purposes of this study was to compare these data with the diffuse scattering near the small-angle Bragg reflections.…”

Perturbative theory of grazing-incidence diffuse nuclear resonant scattering of synchrotron radiation

“…Conversely, the resonant Mössbauer medium is absorptive and gyrotropic and reciprocity can not be proved to hold in general. 46,59 In fact, the violation of reciprocity in scattering on absorptive and grotropic media is still the subject of both experimental 61,63,64 and theoretical 46,62 works.…”

“…Conversely, the resonant Mössbauer medium is absorptive and gyrotropic and reciprocity can not be proved to hold in general. 46,59 In fact, the violation of reciprocity in scattering on absorptive and grotropic media is still the subject of both experimental 61,63,64 and theoretical 46,62 works. 60 Nevertheless, for the special case under discussion, when all hyperfine magnetic fields are aligned parallel/antiparallel to the wave vector, one may verify that reciprocity exactly holds.…”