Possible superconductivity in multi-layer-graphene by application of a gate voltage

The carrier density in tens of nanometers thick graphite samples (multi-layer-graphene, MLG) has been modified by applying a gate voltage (V-g) perpendicular to the graphene planes. Surface potential microscopy shows inhomogeneities in the carrier density (n) in the sample near surface region and under different values of V-g at room temperature. Transport measurements on different MLG samples reveal that under a large enough applied electric field these regions undergo a superconducting-like transition at T less than or similar to 17K. A magnetic field applied parallel or normal to the graphene layers suppresses the transition without changing appreciably the transition temperature. (C) 2014 Elsevier Ltd. All rights reserved.