Atomic structure based simulation of X-ray scattering front strained superlattices

The X-ray scattering from strained superlattices is simulated using the pos itions of all individual atoms, determined by minimizing the strain energy of the structure, and the kinematic approximation (atomistic kinematic theo ry, AKT). For thin epilayers the agreement with dynamical diffraction theor y (DT) is very close in the vicinity of a reciprocal lattice point, even in the case of large strain. Serious flaws in two of the five tested, widely used commercial DT simulation programs art: revealed. DT in the two-beam ap proximation yields incomplete large angle diffraction scans since the solut ion is developed around only one reciprocal lattice vector, while in AKT al l possible scattering vectors are (implicitly) considered.