Low dimensional features of graphene nanostructure stability and vibrational characteristics (Review)

Abstract

The densities of phonon states and their related vibrational thermodynamic characteristics, such as heat capacity, root-mean-square displacement of atoms, and thermal expansion, are calculated and analyzed at the microscopic level for graphite and graphene nanoformations, such as nanofilms and nanotubes. The simulation model is based on experimental data without a priori assumptions as to the nature and potentials of interatomic interactions, and is compared to them only after, which yields a good agreement. The quasi-flexural and torsional modes, which are inherent to graphene nanotubes, are considered and their contribution to the low temperature vibrational characteristics are analyzed. The impact that extended defects, such as graphite intercalation with transition metals, step-edges on graphene nanofilms, and edges of a graphene single layer on a substrate, have on the phonon spectrum and vibrational characteristics is analyzed. The calculated results are compared to the experimental data.