ABSTRACT
Carbon atoms can form various condensed-matter systems with unique geometric structures, mainly owing to four active atomic orbitals. Zero- to three-dimensional carbon-related systems cover diamond, graphite, graphene, graphene nanoribbons, carbon nanotubes and carbon fullerene. The magneto-optical excitations arising from two groups of quantized Landau subbands (LSs) in graphite or N groups of LLs in graphenes could be evaluated using the generalized tight-binding model. Specifically, angle-resolved photoemission spectroscopy (ARPES), a powerful tool in the direct identification of energy bands, is utilized to examine two/three pairs of Dirac-cone structures in Simple hexagonal (AA)-stacked bilayers/trilayers. The predicted band structures, energy spectra and optical excitations can be verified by ARPES, scanning tunneling spectroscopy (STS) and optical spectroscopy, respectively. The quantized LLs of the partially flat bands and the lowest sombrero-shaped band have been verified by magneto-Raman spectroscopy for a large rhombohedral graphites (ABC) domain in a graphene multilayer flake.
