Dirac cone in α-graphdiyne: a first-principles study

Abstract We investigate the Dirac cone in α -graphdiyne, which is a predicted flat one-atom-thick allotrope of carbon using first-principles calculations. α -graphdiyne is derived from graphene where two acetylenic linkages (-C ≡C-) are inserted into the single bonds (-C-C-). Thus, α -graphdiyne possesses a larger lattice constant which subsequently affects its electronic properties. Band structures show that α -graphdiyne exhibits similar Dirac points and cone to graphene. Further, the tight-binding method is used to exploit the linear dispersion in the vicinity of Dirac points. Thanks to the larger lattice constant, α -graphdiyne yields a lower Fermi velocity, which might make itself an ideal material to serve the anomalous integer quantum Hall effect.