Temperature dependent measurements on two decoupled graphene monolayers

Single and coupled bilayer graphene exhibit outstanding electronic properties, making them candidates for new electronic devices. Apart from these, bilayer systems consisting of two decoupled monolayers can be produced. We investigate the electronic properties of such a decoupled double layer system formed by the folding of a single one. Electronic transport through these two very closely spaced monolayers is analyzed, varying carrier concentration, magnetic field and temperature from 1.5 up to 50 K. Using the temperature dependence of the Shubnikov-de Haas oscillations observed in the longitudinal resistance, the cyclotron masses for electrons and holes in both layers are obtained for different carrier concentrations. These values are higher than those expected from a single graphene monolayer, confirming a reduced Fermi velocity in such twisted samples. (C) 2009 Elsevier B.V. All rights reserved.