Generalized Laue dynamical theory for x-ray reflectivity at low and high incidence angles on strained multilayers
- Centro Nazionale Ricerca e Sviluppo Materiali (PASTIS-CNRSM), Strada Statale 7 Appia km 712, I-72100 Brindisi (Italy)
In this work, we present a generalized dynamical theory for strained multilayers within the Laue formalism valid for x-ray Bragg diffraction. In the generalized theory we take into account all the four solutions of the secular equation, the asymptotic sphericity of the dispersion surface, the difference between electric and displacement fields, and the boundary conditions of continuity at the heterointerfaces for the tangential components of the electric and magnetic fields. Only the following approximations are made: to consider a two-beam case, and to neglect quadratic terms of the dielectric susceptibility. Our general equations give the correct x-ray reflectivity in the whole angular range between 0 and {pi}/2, i.e., also very far from the Bragg peaks. Great differences between the predictions of the conventional and generalized theories are obtained in several cases, for important features of the rocking curves, like angular position, peak intensity, and full width at half maximum of superlattice satellite or epitaxial layer peaks. We discuss in detail the following cases for which only the generalized theory describes correctly the x-ray scattering: coplanar diffraction (i) very far from the Bragg condition, (ii) near to the Bragg condition for strong asymmetric reflections, and (iii) for highly mismatched heterostructures. {copyright} {ital 1997} {ital The American Physical Society}
- OSTI ID:
- 543818
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 56, Issue 15; Other Information: PBD: Oct 1997
- Country of Publication:
- United States
- Language:
- English
Similar Records
One dimensional focusing with high numerical aperture multilayer Laue lens
Multilayers are enabling new science with x-ray free electron lasers