Communication: Investigation of the electron momentum density distribution of nanodiamonds by electron energy-loss spectroscopy

Abstract

The electron momentum distribution of detonation nanodiamonds (DND) was investigated by recording electron energy-loss spectra at large momentum transfer in the transmission electron microscope (TEM), which is known as electron Compton scattering from solid (ECOSS). Compton profile of diamond film obtained by ECOSS was found in good agreement with prior photon experimental measurement and theoretical calculation that for bulk diamond. Compared to the diamond film, the valence Compton profile of DND was found to be narrower, which indicates a more delocalization of the ground-state charge density for the latter. Combining with other TEM characterizations such as high-resolution transmission electron spectroscopy, diffraction, and energy dispersive X-ray spectroscopy measurements, ECOSS was shown to be a great potential technique to study ground-state electronic properties of nanomaterials.

Compton profile of few-layer graphene investigated by electron energy-loss spectroscopy

“…The EELS is acquired by tilting the incident beam through a few degrees (~5°) for ECOSS measurement so that only large-angle-scattered electrons are collected 9,10 . The ECOSS technique has proven to be an important alternative for experimentally investigating the electron momentum density distribution of nanomaterials 11,12 .…”

Investigation of Electron Momentum Density in Carbon Nanotubes Using Transmission Electron Microscopy

“…The CPs of both MWCNTs and SWCNTs are sharper than that of the bulk graphite, which indicates a larger delocalization of valence electrons in the CNTs and especially for SWCNTs. This is a common feature of nanomaterials in Compton scattering experiments, where a weaker solid-state effect will result in a higher delocalization of valence electrons for nanomaterials (Metz et al, 1999; Mishra et al, 2011; Moscovici et al, 1995; Reiter et al, 2013; Feng et al, 2015; Feng et al, 2019). In graphite or MWCNTs, the electrons form π bonds between two layers via weak van der Walls forces, while in monolayer SWCNTs, the π bonds are not complete and the electrons forming such bonds behave almost as delocalized electrons, associated with the curving graphene layer by means of dangling bonds.…”