Low energy electron reflection intensities from layered transition metal dichalcogenides as derived by scattering matrix calculations

Abstract

The dynamical scattering matrix method is used to obtain reflection intensities for the incidence of low energy electrons in the range 0.25-15.0 eV on various members of the layered transition metal dichalcogenide family: 2H-MoSe₂, 1T-ZrS₂ and 2H-NbSe₂. In particular, the results of these diffraction calculations, based on a simple pseudopotential, are compared with experimental spectra obtained using the total (net) current technique. In the calculation, an incident energy dependent absorption potential is estimated by a combination of results from dielectric response theory together with experimental values of the high energy electron dielectric loss function. Comments are made regarding the apparent coincidence of low order kinematical Bragg reflection conditions with features present in the experimental and dynamical calculation spectra. As in previous work, it is concluded that it is essentially the crystal structure that determines the intensity spectrum and that a precise description of the individual scattering events is not as necessary as might first appear.