2010/05/27 by Joaquín E. Drut, Drut, Joaquín E., Timo A. Lähde +3
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Graphene research and applications #Quantum and electron transport phenomena #Strongly Correlated Electrons (cond-mat.str-el) #Topological Materials and Phenomena #cond-mat.str-el
paper · pdf · doi:10.48550/arxiv.1005.5089
4 pages, 3 figures
arxiv created 2010/05/27 · openalex publication_date 2010/05/27 · arxiv updated 2016/08/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The electrical conductivity of suspended graphene has recently been measured for the first time, and found to behave as σ~ √(|n|) as expected for Dirac quasiparticles at large carrier density. The charge inhomogeneity is strongly reduced in suspended samples, which revealed an unexpected insulating trend in σ(T). Above a transitional density n*, the temperature dependence was found to revert to metallic. We show that these features of the DC conductivity are consistent with a simple model of gapped Dirac quasiparticles, with specific signatures of a gap in the vicinity of the charge-neutrality point. Our findings are reminiscent of the conductivity profile in semiconducting materials, exhibiting a thermal activation for T ≥ T and a weakly T-dependent background for T ≤ T, where T is given by the saturation density n associated with the residual charge inhomogeneity. We discuss possible origins of a bandgap in graphene as well as alternative scenarios.