The electronic thickness of graphene.
- Rickhaus P Solid State Physics Laboratory, ETH Zürich, CH-8093 Zürich, Switzerland.
- Liu MH Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan.
- Kurpas M Institute of Physics, University of Silesia in Katowice, 41-500 Chorzów, Poland.
- Kurzmann A Solid State Physics Laboratory, ETH Zürich, CH-8093 Zürich, Switzerland.
- Lee Y Solid State Physics Laboratory, ETH Zürich, CH-8093 Zürich, Switzerland.
- Overweg H Solid State Physics Laboratory, ETH Zürich, CH-8093 Zürich, Switzerland.
- Eich M Solid State Physics Laboratory, ETH Zürich, CH-8093 Zürich, Switzerland.
- Pisoni R Solid State Physics Laboratory, ETH Zürich, CH-8093 Zürich, Switzerland.
- Taniguchi T National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
- Watanabe K National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
- Richter K Institute of Theoretical Physics, University of Regensburg, D-93040 Regensburg, Germany.
- Ensslin K Solid State Physics Laboratory, ETH Zürich, CH-8093 Zürich, Switzerland.
- Ihn T Solid State Physics Laboratory, ETH Zürich, CH-8093 Zürich, Switzerland.
- 2020-03-24
Published in:
- Science advances. - 2020
English
When two dimensional crystals are atomically close, their finite thickness becomes relevant. Using transport measurements, we investigate the electrostatics of two graphene layers, twisted by θ = 22° such that the layers are decoupled by the huge momentum mismatch between the K and K' points of the two layers. We observe a splitting of the zero-density lines of the two layers with increasing interlayer energy difference. This splitting is given by the ratio of single-layer quantum capacitance over interlayer capacitance C m and is therefore suited to extract C m. We explain the large observed value of C m by considering the finite dielectric thickness d g of each graphene layer and determine d g ≈ 2.6 Å. In a second experiment, we map out the entire density range with a Fabry-Pérot resonator. We can precisely measure the Fermi wavelength λ in each layer, showing that the layers are decoupled. Our findings are reproduced using tight-binding calculations.
- Language
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- English
- Open access status
- gold
- Identifiers
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- DOI 10.1126/sciadv.aay8409
- PMID 32201727
- Persistent URL
- https://sonar.ch/global/documents/250483
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