Leitner Michael, Sepiol Bogdan, Stadler Lorenz-Mathias, Pfau Bastian, Vogl Gero
Fakultät für Physik, Universität Wien, Strudlhofgasse 4, 1090 Wien, Austria.
Nat Mater. 2009 Sep;8(9):717-20. doi: 10.1038/nmat2506. Epub 2009 Jul 26.
Knowledge of atomic diffusion is a fundamental issue in synthesis and stability of materials. Direct studies of the elementary diffusion event, that is, how the individual atoms 'jump', are scarce, as the available techniques are limited to selected systems. Here we show how by monitoring the spatial and temporal variations of the scattered coherent X-ray intensity the diffusion of single atoms can be studied. This is demonstrated for the intermetallic alloy Cu(90)Au(10). By measuring along several directions in reciprocal space, we can elucidate the dynamical behaviour of single atoms as a function of their neighbourhood. This method, usually referred to as X-ray photon correlation spectroscopy (XPCS), does not rely on specific atomic species or isotopes and can thus be applied to almost any system. Thus, given the advent of the next-generation X-ray sources, XPCS has the potential to become the main method for quantitatively understanding diffusion on the atomic scale.
原子扩散知识是材料合成与稳定性的一个基本问题。对基本扩散事件（即单个原子如何“跳跃”）的直接研究很少，因为现有技术仅限于特定系统。在这里，我们展示了如何通过监测散射相干X射线强度的空间和时间变化来研究单个原子的扩散。这在金属间合金Cu(90)Au(10)中得到了证明。通过在倒易空间的几个方向上进行测量，我们可以阐明单个原子作为其邻域函数的动力学行为。这种方法通常称为X射线光子相关光谱学（XPCS），不依赖于特定的原子种类或同位素，因此几乎可以应用于任何系统。因此，鉴于下一代X射线源的出现，XPCS有潜力成为定量理解原子尺度扩散的主要方法。
