Reflection High Electron Research Articles

Modified multislice theory for calculating the energy-filtered inelastic images in REM and HREM

Using a method introduced by Wang, the multiple plasmon diffuse scattering (PDS) can be included in dynamical calculation for reflection electron microscopy (REM) and high resolution electron microscopy (HREM). The calculated electron intensity distribution would be the combination of elastic and inelastic scattered electrons. In some experimental cases, it is desirable that the energy filtered inelastic image (EFIM) could be simulated. The purpose of this paper is to suggest a modified multislice theory for calculating the EFIM in REM and HREM.Considering an electron travelling in medium b with distance x parallel to an interface from medium a, due to the plasmon excitation, the wavelength of the electron is perturbed by its energy-loss during the propagation. The modified phase grating function (PGF) of a thin potential slice ▵z might be written as [1]:(1a)with(1b)

Azimuthal dependence of reflection high resolution electron energy loss of Si(111)(2×1)

Abstract High Resolution Electron Energy Loss Spectroscopy has been used, with low energy of the primary beam and azimuthal resolution, to study the anisotropy of surface dielectric properties of Si(111)(2 × 1), in the range of the surface electronic excitations. By eliminating the effect of the kinematic prefactor, we are able to obtain from the data the surface Loss Function. Its dependence on q ∥ and ω is discussed in term of a model of surface dielectric function.