The Effective Fine-Structure Constant of Freestanding Graphene Measured in Graphite

Abstract

Weakly Interacting Graphene Many unusual properties of graphene are a consequence of the Dirac dispersion of its electrons—a linear relationship between an electron's momentum and energy. Naïvely, this dispersion leads to the conclusion that electrons in graphene are strongly affected by mutual electrostatic interactions; however, there is little experimental evidence for strong interaction. Reed et al. (p. 805 ) resolved this discrepancy by using inelastic x-ray scattering spectra of graphite (which consists of loosely bound layers of graphene) to estimate how much the electric field was damped by the presence of mobile charge carriers. In fact, damping was strong at distances in excess of 1 nanometer, suggesting that graphene is more weakly interacting than was assumed.