Magnetoconductance Oscillations and Evidence for Fractional Quantum Hall States in Suspended Bilayer and Trilayer Graphene

We report pronounced magnetoconductance oscillations observed on suspended bilayer and trilayer graphene devices with mobilities up to 270000 cm(2)/V s. For bilayer devices, we observe conductance minima at all integer filling factors v between 0 and -8, as well as a small plateau at v = 1/3. For trilayer devices, we observe features at v = -1, -2, -3, and -4, and at v similar to 0.5 that persist to 4.5 K at B 8 T. All of these features persist for all accessible values of V-g and B, and could suggest the onset of symmetry breaking of the first few Landau levels and fractional quantum Hall states.