Elastic electron fine structure: Application to the study of local order

Oscillations are found in the integrated intensity of elastic electrons scattered from amorphous Si. These oscillations are attributed to the multiple scattering of elastic waves between a central atom and its neighbors, an effect which is similar to but more general than that found in extended x-ray absorption fine structure and related phenomena. The Fourier analysis of the signal obtained with amorphous Si produces a dominant peak which closely corresponds to twice the nearest-neighbor distance. The result of a first-principle multiple-scattering calculation reproduces remarkably well in the experiment and clearly demonstrates the physical processes responsible for these oscillations.