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Double-gated graphene devices provide an important platform for understanding electrical and optical properties of graphene. Here we present transport measurements of single layer, bilayer and trilayer graphene devices with suspended top…

Mesoscale and Nanoscale Physics · Physics 2015-06-05 J. Velasco , Y. Lee , L. Jing , G. Liu , W. Bao , C. N. Lau

We introduce a novel two-dimensional electronic system with ultrastrong interlayer interactions, namely twisted bilayer graphene with a large twist angle, as an ideal ground for realizing interlayer-coherent excitonic condensates. In these…

Mesoscale and Nanoscale Physics · Physics 2022-12-20 Dohun Kim , Byungmin Kang , Yong-Bin Choi , Kenji Watanabe , Takashi Taniguchi , Gil-Ho Lee , Gil Young Cho , Youngwook Kim

The quantum Hall effect near the charge neutrality point in bilayer graphene is investigated in high magnetic fields of up to 35 T using electronic transport measurements. In the high field regime, the eight-fold degeneracy in the zero…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 Y. Zhao , P. Cadden-Zimansky , Z. Jiang , P. Kim

Bilayer graphene -- two coupled single graphene layers stacked as in graphite -- provides the only known semiconductor with a gap that can be tuned externally through electric field effect. Here we use a tight binding approach to study how…

Mesoscale and Nanoscale Physics · Physics 2010-04-29 Eduardo V. Castro , N. M. R. Peres , J. M. B. Lopes dos Santos , F. Guinea , A. H. Castro Neto

We report on charge detection in electrostatically-defined quantum dot devices in bilayer graphene using an integrated charge detector. The device is fabricated without any etching and features a graphite back gate, leading to high quality…

Mesoscale and Nanoscale Physics · Physics 2019-10-18 A. Kurzmann , H. Overweg , M. Eich , A. Pally , P. Rickhaus , R. Pisoni , Y. Lee , K. Watanabe , T. Taniguchi , T. Ihn , K. Ensslin

Bilayer graphene has a unique electronic structure influenced by a complex interplay between various degrees of freedom. We probe its chemical potential using double bilayer graphene heterostructures, separated by a hexagonal boron nitride…

Mesoscale and Nanoscale Physics · Physics 2014-07-08 Kayoung Lee , Babak Fallahazad , Jiamin Xue , David C. Dillen , Kyounghwan Kim , Takashi Taniguchi , Kenji Watanabe , Emanuel Tutuc

The edge states of the quantum Hall and fractional quantum Hall effect of a two-dimensional electron gas provide key access to the excitations of the bulk. Here we demonstrate controlled transmission of edge states in bilayer graphene.…

Mesoscale and Nanoscale Physics · Physics 2018-02-06 Jing Li , Hua Wen , Kenji Watanabe , Takashi Taniguchi , Jun Zhu

We use low-temperature scanning gate microscopy (SGM) to investigate the breakdown of the quantum Hall regime in an exfoliated bilayer graphene flake. SGM images captured during breakdown exhibit intricate patterns of "hotspots" where the…

Mesoscale and Nanoscale Physics · Physics 2013-03-05 M. R. Connolly , R. K. Puddy , D. Logoteta , P. Marconcini , M. Roy , J. Griffths , G. A. C. Jones , P. Maksym , M. Macucci , C. G. Smith

We report tunneling spectroscopy experiments on a bilayer graphene double quantum dot device that can be tuned by all-graphene lateral gates. The diameter of the two quantum dots are around 50 nm and the constrictions acting as tunneling…

Mesoscale and Nanoscale Physics · Physics 2015-03-19 Christian Volk , Stefan Fringes , Bernat Terrés , Jan Dauber , Stephan Engels , Stefan Trellenkamp , Christoph Stampfer

Graphene nanostructures exhibit an intrinsic advantage in relation to the gate delay in three-terminal devices and provide additional benefits when operate in the quantum capacitance limit. In this paper, we developed a simple model that…

Mesoscale and Nanoscale Physics · Physics 2011-08-02 George S. Kliros

We present transport measurements through an electrostatically defined bilayer graphene double quantum dot in the single electron regime. With the help of a back gate, two split gates and two finger gates we are able to control the number…

Mesoscale and Nanoscale Physics · Physics 2020-04-22 Luca Banszerus , Samuel Möller , Eike Icking , Kenji Watanabe , Takashi Taniguchi , Christian Volk , Christoph Stampfer

Realizing graphene's promise as an atomically thin and tunable platform for fundamental studies and future applications in quantum transport requires the ability to electrostatically define the geometry of the structure and control the…

Mesoscale and Nanoscale Physics · Physics 2019-03-20 Rebeca Ribeiro-Palau , Shaowen Chen , Yihang Zeng , Kenji Watanabe , Takashi Taniguchi , James Hone , Cory R. Dean

We study the conductance of a biased bilayer graphene flake with monolayer nanoribbon contacts. We find that the transmission through the bilayer ribbon strongly depends on the applied bias between the two layers and on the relative…

Mesoscale and Nanoscale Physics · Physics 2011-05-18 J. W. González , H. Santos , E. Prada , L. Brey , L. Chico

We investigate electronic transport in dual-gated twisted bilayer graphene. Despite the sub-nanometer proximity between the layers, we identify independent contributions to the magnetoresistance from the graphene Landau level spectrum of…

Twisted bilayer graphene with a twist angle of around 1.1{\deg} features a pair of isolated flat electronic bands and forms a strongly correlated electronic platform. Here, we use scanning tunneling microscopy to probe local properties of…

We report a study of one-dimensional subband splitting in a bilayer graphene quantum point contact in which quantized conductance in steps of $4\,e^2/h$ is clearly defined down to the lowest subband. While our source-drain bias spectroscopy…

Mesoscale and Nanoscale Physics · Physics 2018-12-26 R. Kraft , I. V. Krainov , V. Gall , A. P. Dmitriev , R. Krupke , I. V. Gornyi , R. Danneau

Magic-angle twisted bilayer graphene (MATBG) combines in one single material different phases like insulating, metallic and superconducting. These phases and their in-situ tunability make MATBG an important platform for the fabrication of…

We present low temperature transport measurements on dual-gated suspended trilayer graphene in the quantum Hall (QH) regime. We observe QH plateaus at filling factors {\nu}=-8, -2, 2, 6, and 10, in agreement with the full-parameter tight…

Mesoscale and Nanoscale Physics · Physics 2017-11-22 Yongjin Lee , Jairo Velasco , David Tran , Fan Zhang , Wenzhong Bao , Lei Jing , Kevin Myhro , Dmitry Smirnov , Chun Ning Lau

A gate-defined quantum dot in bilayer graphene is utilized as a sensitive electrometer for probing the charge density of its environment. Under the influence of a perpendicular magnetic field, the charge carrier density of the channel…

Electrostatic confinement of charge carriers in bilayer graphene provides a unique platform for carbon-based spin, charge or exchange qubits. By exploiting the possibility to induce a band gap with electrostatic gating, we form a versatile…