Credit: B. Terrés, L. A. Chizhova, F. Libisch, J. Peiro, D. Jörger, S. Engels, A. Girschik, K. Watanabe, T. Taniguchi, S. V. Rotkin, J. Burgdörfer, C. Stampfer
This graph shows electrical conductance, G, of electrons (black) and holes (red) in graphene nanoconstriction (shown in SEM image), as a function of electron/hole wave vector (momentum) showing characteristic steps (quantization of conductance) as indicated by arrows.