Electron energy loss studies of the transition metal dichalcogenides

Abstract

An analysis of electron energy loss spectra of some 12 transition metal dichalcogenides has given useful information towards the understanding of the band structures of these layer-type solids. Using the experience gained from studying graphite in which the valence band consists of two groups, namely π and σ bands, a similar band scheme has also been established for the transition metal dichalcogenides. The plasma resonance energies of π electrons are discussed in terms of the screening by σ electrons and the finite oscillator coupling between the two valence bands. Single electron interband excitations have been observed, which are expected to form the basis for further detailed study into the band structures of these materials. Many atomic-like excitations associated with the core d and core f electrons have also been observed.