Theoretical studies of EELS in carbon structures

Graphene nano-ribbons (GNRs) are promising materials for applications in the field of nanotechnology, which requires detailed control of the material at the atomic level. Therefore, a detailed characterisation with atomic resolution is essential. Recently, the improvements of Electron Energy Loss Spectroscopy (EELS) technique made observation of electronic states in a single atom possible. The interpretation of EELS spectra is through fingerprint matching compared to the spectrum from the reference material, however, so far there is no report to indicate the detailed spectral feature based on systematic investigation for the EELS spectra of GNRs. In this project, in order to demonstrate the characteristic spectral features for fingerprint, ab initio EELS calculations for GNRs were performed for different atomic sites, edge shapes, ribbon widths and edge modifications. As a result, theoretical EELS spectra showed the different spectral features for each condition. These relations indicate it is possible to convert experimental data into the local atomic arrangement and chemical-bonding states in GNRs.