Seyoung Kim, Kayoung Lee, and E. Tutuc, Phys. Rev. Lett. 107, 016803 (2011).

1. Phase transitions in Dual-Gated Bilayer GrapheneGregory S. Boebinger, Florida State University, DMR 0654118DC Field Facility (a) (b) Bilayer graphene, consisting of two layers of carbon atoms, is patterned into a Hall bar and covered with two gates to enable independent control of the number of electrons in each layer and, hence, the electric field between the layers. In a high magnetic field, these two-dimensional layers of electrons form a quantized Hall effect where the Hall resistance in quantized in units of e2/h. As the perpendicular magnetic field is increased, we find that the resistivity is peaked at low electric fields and diverges at high electric fields. This behavior is understood in terms of the degeneracy of the electronic states in the graphene bilayer. (c) Resistivity plotted as a function of the front gate and rear gate voltage. B) Resistivity and Hall effect as a function of carrier concentration. C) Resistivity as a function of electric field and magnetic field. Seyoung Kim, Kayoung Lee, and E. Tutuc, Phys. Rev. Lett. 107, 016803 (2011).

2. Phase transitions in Dual Gated Bilayer GrapheneGregory S. Boebinger, Florida State University, DMR 0654118DC Field Facility Graphene samples were originally fabricated with scotch tape. In this work graphene samples are created and precision gates applied to both the front and back surfaces using modern microelectronic techniques in the Microelectronics Laboratory at the University of Texas (funded by the NSF National Infrastructure Nanofabrication Network). Samples were brought to the Magnet Lab for measurements in high magnetic fields. Ultimately, this work shows that graphene can be fabricated with techniques used in the semiconductor industry and could be used as the basis for the next generation of electronics for high speed devices. Seyoung Kim, Kayoung Lee, and E. Tutuc, Phys. Rev. Lett. 107, 016803 (2011).