DIRECT IMAGING OF THE VALENCE ELECTRONIC-STRUCTURE OF SOLIDS BY (E,2E) SPECTROSCOPY

The spectral momentum density rho(E, q) of the valence electrons of so lid thin films of annealed amorphous carbon, amorphous silicon and sil icon carbide has been measured using (e,2e) spectroscopy. Substantial contrast has been observed between the images of the three momentum de nsities, which show not only well-defined energy band dispersion in th e three materials, but also the antisymmetric gap due to the unequal p otentials between the Si and C sites in the silicon carbide. The relat ion between the three momentum densities is explained within the frame work of the one-electron band theory of solids.