Atomic Migration Studies with X-Ray Photon Correlation Spectroscopy

Abstract

Abstract. The new technique of atomic-scale X-ray Photon Correlation Spectroscopy (aXPCS) makes use of a coherent X-ray beam to study the dynamics of various processes in condensed matter systems. Particularly atomistic migration mechanisms are still far from being understood in most of intermetallic alloys and in amorphous systems. Special emphasis must be given to the opportunity to measure atomistic diffusion at relatively low temperatures where such measurements were far out of reach with previously established methods. The importance of short-range order is demonstrated on the basis of Monte Carlo simulations.

Beam-induced atomic motion in alkali borate glasses

“…The full potential of the method has been realized by the first demonstration of atomic-scale XPCS (aXPCS) by Leitner et al [10]. Since then it has been applied in several crystalline [11] and amorphous solids [12][13][14].…”

Chemical ordering beyond the superstructure in long-range ordered systems

“…Apart from exemplifying the concepts as done here, it is also conceivable to use simulations of diffuse scattering as substitutes for experimental data when short-range order information is necessary. Specifically, this pertains to the problem of data modelling in atomic-scale x-ray photon correlation spectroscopy (aXPCS) (Leitner 2012, Stana et al 2014, where in the simplest approximation (Leitner and Vogl 2011) the measured  q -dependent correlation times are a product of the short-range order diffuse scattering and a factor depending on the jump geometry. Only in rare cases (Leitner et al 2009) experimental short-range order data is available for the same composition and temperature range , or simple qualitative models such as nearest-neighbour site exclusions (Stana et al 2013) can describe the data.…”