327-2139-00L  Diffraction Physics in Materials Science

SemesterSpring Semester 2021
LecturersR. Erni
Periodicityyearly recurring course
Language of instructionEnglish

AbstractThe lecture focuses on diffraction and scattering phenomena in materials science beyond basic Bragg diffraction. Introducing the 1st-order Born approximation and Kirchoff’s theory, diffraction from ideal and non-ideal crystals is treated including, e.g., temperature and shape effects, ordering phenomena, small-angle scattering and dynamical diffraction theories.
Objective• To become familiar with advanced diffraction phenomena in order to be able to explore the structure and properties of (solid) matter and their defects.
• To build up a generally applicable and fundamental theoretical understanding of scattering and diffraction effects.
• To learn about limitations of the methods and the underlying theory which is commonly used to analyze diffraction data.
ContentThe course provides a general introduction to advanced diffraction phenomena in materials science. The lecture series covers the following topics: derivation of a general scattering theory based on Green’s function as basis for the introduction of the first-order Born approximation; Kirchhoff’s diffraction theory with its integral theorem and the specific cases of Fresnel and Fraunhofer diffraction; diffraction from ideal crystals and diffraction from real crystals considering temperature effects expressed by the temperature Debye-Waller factor and by thermal diffuse scattering, atomic size effects expressed by the static Debye-Waller factor and diffuse scattering due to the modulation of the Laue monotonic scattering as a consequence of local order or clustering; the basics of small-angle scattering; and finally approaches used to treat dynamical diffraction are introduced and exemplified by performing simulations. In addition, the specifics of X-ray, electron and neutron scattering are being discussed. The course is complemented by a lab visit, live demos, selected exercises and short topical presentations given by the participants.
Lecture notesFull-text script is available covering within about 100 pages the core topics of the lecture and all necessary derivations.
Literature- Diffraction Physics, 3rd ed., J. M. Cowley, Elsevier, 1994.
- X-Ray Diffraction, B. E. Warren, Dover, 1990.
- Diffraction from Materials, 2nd ed., L. H. Schwartz, J. B. Cohen, Springer, 1987.
- X-Ray Diffraction – In Crystals, Imperfect Crystals and Amorphous Bodies, A. Guinier, Dover, 1994.
- Aberration-corrected imaging in transmission electron microscopy, 2nd ed., R. Erni, Imperial College Press, 2015.
Prerequisites / NoticeBasics of crystallography and the concept of reciprocal space, basics of electromagnetic and particle waves (but not mandatory)