title: Direct Observation of a Gate Tunable Band Gap in Electrical Transport in ABC-Trilayer Graphene.
abstract: Few layer graphene systems such as Bernal stacked bilayer and rhombohedral (ABC-) stacked trilayer offer the unique possibility to open an electric field tunable energy gap. To date, this energy gap has been experimentally confirmed in optical spectroscopy. Here we report the first direct observation of the electric field tunable energy gap in electronic transport experiments on doubly gated suspended ABC-trilayer graphene. From a systematic study of the nonlinearities in current versus voltage characteristics and the temperature dependence of the conductivity, we demonstrate that thermally activated transport over the energy-gap dominates the electrical response of these transistors. The estimated values for energy gap from the temperature dependence and from the current voltage characteristics follow the theoretically expected electric field dependence with critical exponent 3/2. These experiments indicate that high quality few-layer graphene are suitable candidates for exploring novel tunable terahertz light sources and detectors.
authors.affiliation: Centre for Graphene Science, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QF, United Kingdom.
authors.forename: Tymofiy
authors.initials: T
authors.lastname: Khodkov
authors.affiliation: Centre for Graphene Science, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QF, United Kingdom.
authors.forename: Ivan
authors.initials: I
authors.lastname: Khrapach
authors.affiliation: Centre for Graphene Science, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QF, United Kingdom.
authors.forename: Monica Felicia
authors.initials: MF
authors.lastname: Craciun
authors.affiliation: Centre for Graphene Science, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QF, United Kingdom.
authors.forename: Saverio
authors.initials: S
authors.lastname: Russo
keywords: Trilayer graphene; band gap; double gated