An ILEED study of the density-of-states function of tungsten

Abstract

Electron energy loss spectroscopy (EELS) and inelastic low-energy electron diffraction (ILEED) have been combined to study the density-of-states (DOS) function in tungsten. The EELS spectra measured as a function of the primary electron energy E p ( E p < 100 eV) by means of a CMA spectrometer are interpreted in terms of the angular-resolved EELS taking into account the electron diffraction phenomena. As a result, we could correlate the EELS spectrum measured at a particular value of E p with the one-dimensional DOS function. In addition, the LEED intensity theory, which we used in this work, has permitted us to estimate whether the correlation should be made with the surface-localized DOS (i.e. SDOS) or the bulk DOS (i.e. BDOS). Our experimental ILEED results are in good agreement with the theoretical DOS function published by Christensen and Feuerbacher [Phys. Rev. B 10 (1974) 2349]. In particular the energy gap in the theoretical electron structure along the [110] direction has been confirmed experimentally.