This chapter reviews the properties and phase transitions of C60 and C20 solid fullerenes under high pressures through density functional tight binding simulations, augmented by an empiri cal van der Waals force. The geometric structures of C60 molecules situated in the solid fcc phase are considerably changed under compression due to variations in the type of hybridization of carbon atoms, and the HOMO-LUMO gap dramatically decreases in response to the overlap of n orbitals from neighboring C60 molecules. For C20 solid fullerene, three new carbon allotropes have been revealed by cold compression. The three predicted structures are shown to be ener getically more favorable and stable than C20 molecule. The volume compression calculations suggest that phase III has a large bulk modulus (427 GPa) and a bandgap of 5.1 eV. The results indicate that C20 solid fullerene is a potential building block for transparent superhard carbon with more advantages than graphite. We believe that the high-pressure study of small fullerenes will continue to be a rewarding field of study in the future as the advance in synthesis technology of small fullerene.
|Title of host publication||Carbon Nanomaterials Sourcebook|
|Subtitle of host publication||Graphene, Fullerenes, Nanotubes, and Nanodiamonds|
|Number of pages||13|
|Publication status||Published - 6 Apr 2016|
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Materials Science(all)