Spatially Resolved Electron Energy-Loss Spectroscopy, a Tool to Verify Electronic Structure Calculations in Nanostructured Materials

摘要

Modern mcroscopy allows a direct comparison between experimental results and the atomic and electronic structure as obtained by state of the art ab-initio calculations. The phase reconstruction technique allows one to determine the positions of atomic columns with an accuracy of about 30pm. The atomic structure can be studied directly (without computer simulation or reconstruction) with Z-contrast imaging and contains the atomic structure. The electronic structure with atomic column spatial resolution can be determined with spatially-resolved electron energy-loss spec-troscopy. We will show that the atomic calculations and micrographs of a copper doped aluminum grain boundary agrees within the errors of theory and experiments (30pm). The electronic structure as determined by EELS and by density functional theory agrees well enough to apply this combination to the Si/SiO_2 interface and determine the structure of this complicated heterogeneous interface.