Anjan Gupta (Indian Institute of Technology, Kanpur), le 12 juin 2012 à 9h30 en salle Remy Lemaire (K223) de l’Institut Néel, Séminaire NANO
Abstract : Graphene is the only realization of a nearly ideal two-dimensional conductor on a chip with several unusual consequences arising from its structure and dimensionality. In particular, the conical dispersion in graphene leads to a non-linear rise in the Fermi energy with carrier density leading to a sharp jump in the Fermi energy when it passes through the Dirac point. This leads to some interesting features in local tunnel spectra with the tip acting like a top-gate in addition to the silicon back-gate and the local charge puddles. The same does not happen in bilayer graphene, which shows the usual shift in Fermi energy due to the back-gate induced carriers. In this talk I’ll describe some of our recent STM experiments on single layer and bi-layer graphene and quantitatively discuss the effect of carrier density as controlled by the bottom gate electrode.