Near the Dirac Point of Undoped Graphene (IMAGE) DOE/Lawrence Berkeley National Laboratory Caption Dirac cones of graphene are often drawn with straight sides (left) indicating a smooth increase in energy, but an ARPES spectrum near the Dirac point of undoped graphene (sketched in red at right) exhibits a distinct inward curvature, indicating electronic interactions occurring at increasingly longer range and leading to greater electron velocities -- one of the ways the electronics of semi-metallic graphene differ from a metal's. Credit Lawrence Berkeley National Laboratory Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.