Tunable metal-insulator transition in double-layer graphene heterostructures

By L. Ponomarenko, A.K. Geim, A. Zhukov, R. Jalil, S. Morozov, K. Novoselov, V. Cheianov, Vladimir Fal'ko, Kenji Watanabe, Takashi Taniguchi and 1 more. 2011

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Disordered conductors with resistivity above the resistance quantum h/e(2) should exhibit an insulating behaviour at low temperatures, a universal phenomenon known as a strong (Anderson) localization(1-3). Observed in a multitude of materials, including damaged graphene and its disordered chemical derivatives(4-10), Anderson localization has not been seen in generic graphene, despite its resistivity near the neutrality point reaching approximate to h/e(2) per carrier type(4,5). It has remained a puzzle why graphene is such an exception. Here we report a strong localization and the corresponding metal-insulator transition in ultra-high-quality graphene. The transition is controlled externally, by changing the carrier density in another graphene layer placed at a distance of several nm and decoupled electrically. The entire behaviour is explained by electron-hole puddles that disallow localization in standard devices but can be screened out in double-layer graphene. The localization that occurs with decreasing rather than increasing disorder is a unique occurrence, and the reported double-layer heterostructures presents a new experimental system that invites further studies.

Subfields: Atomic and Molecular Physics, and Optics, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/3a0ea5ba8cf0e42e08b79566f3620a45d5f775e9

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In Atomic and Molecular Physics, and Optics

In Materials Chemistry

Citations in the corpus

Cross-sectional imaging of individual layers and buried interfaces of graphene-based heterostructures and superlattices. (2012, methodology): “only seenafter the transfer of graphene or monolayer hBN on top of an atomically flat substrate, regardless whether it is graphite or hBN. The bubbles occur even when a solvent free technique is used [S1], in which case neither of the two attaching surfaces has been in contact with a liquid. Figure ”
Progress, challenges, and opportunities in two-dimensional materials beyond graphene. (2013, background): “also led to an understanding of the observed “minimal conductivity” in graphene,(243) which results from charge puddles created by the nearby SiO2 substrate.(244,245) Additionally, tunneling field-effect transistors made from graphene/BN or graphene/MoS2 heterostructures have been demonstrated to ha”
Strong interlayer coupling in van der Waals heterostructures built from single-layer chalcogenides (2014, methodology): “(C) band diagram of WSe2/MoS2 hetero-bilayer under photo excitation, depicting (1) absorption and exciton generation in WSe2 and MoS2 single layers, (2) Relaxation of excitons at the MoS2/WSe2 interface driven by the band-offset, (3) Radiative recombination of spatially indirect excitons.”