Massless fermions in multilayer graphitic systems with misoriented layers: Ab initio calculations and experimental fingerprints

We examine how the misorientation of a few stacked graphene layers affects the electronic structure of carbon nanosystems. We present ab initio calculations on bilayer and trilayer systems to demonstrate that the massless fermion behavior typical of single-layered graphene is also found in incommensurate multilayered graphitic systems. We also investigate the consequences of this property on experimental fingerprints, such as Raman spectroscopy and scanning tunneling microscopy (STM). Our simulations reveal that STM images of turbostratic few-layer graphite are sensitive to the layer arrangement. We also predict that the resonant Raman signals of graphitic samples are more sensitive to the orientation of the layers than to their number.