Electron energy-loss spectroscopy in the low-loss region as a characterization tool of electrode materials

Abstract

International audienc

Strong anisotropic influence of local-field effects on the dielectric response ofα-MoO3

“…It is worth noting that thanks to an analogous band to band analysis as that described in section V, we are able to show that this increase of intensity results from the influence of LFE on the transitions from the O-s states towards the t 2g manifold. Local-field effects may thus explain the lack of relative intensity already observed on calculated VEELS spectra without LFE of similar compounds such as TiO 2 and SrTiO 3 32,66. Slight differences are however observed between calculations and experimental spectra concerning the energy position of both A and B structures that are underestimated by 1 eV.…”

Understanding the spectroscopic signatures of Mn valence changes in the valence energy loss spectra of Li-Mn-Ni-O spinel oxides

“…The effect of variations in Mn valency and related structural distortions on experimental valence energy loss experimental spectra was explored using electronic/band-structure calculations and the calculated VEELS spectra. Theoretical spectra and electronic structures from ab initio calculations have already been shown to be useful in interpreting experimental EELS spectra and vice versa [21][22][23]. around 7-10 eV in all phases.…”

“…Comparison with band structure calculations VEELS spectra probe the joint density of states (JDOS) where JDOS is a convolution of valence and conduction density of states [25,26]. Density of states (DOS) calculations are therefore an important step towards understanding spectra features in valence energy loss spectra [21][22][23]. From calculated ELF presented in Fig.…”

“…Through electronic and theoretical spectra calculations it is possible to determine the origin and the nature of interband transitions which contribute to the valence energy loss spectra [21][22][23]29]. The calculated ELF can be expressed as…”

“…These spectroscopic methods have mainly focused on core-loss spectra originating from core states to the unoccupied states in the conduction band. Less attention has been given to valence energy loss spectra comprising valence-to-conduction band and plasmon excitations [21][22][23][24]. One reason for this has to do with the considerably large number of different types of excitations observed in this region as well as the difficulty of interpreting the origin and the nature of these excitations.…”