Milli-Tesla quantization enabled by tuneable Coulomb screening in large-angle twisted graphene

Year: 2025

Type: article

Abstract: The electronic quality of graphene has improved significantly over the past two decades, revealing novel phenomena. However, even state-of-the-art devices exhibit substantial spatial charge fluctuations originating from charged defects inside the encapsulating crystals, limiting their performance. Here, we overcome this issue by assembling devices in which graphene is encapsulated by other graphene layers while remaining electronically decoupled from them via a large twist angle (~10–30°). Doping of the encapsulating graphene layer introduces strong Coulomb screening, maximized by the sub-nanometer distance between the layers, and reduces the inhomogeneity in the adjacent layer to just a few carriers per square micrometre. The enhanced quality manifests in Landau quantization emerging at magnetic fields as low as ~5 milli-Tesla and enables resolution of a small energy gap at the Dirac point. Our encapsulation approach can be extended to other two-dimensional systems, enabling further exploration of the electronic properties of ultrapure devices. While the electronic quality of graphene has significantly improved during the last two decades, charged defects inside encapsulating crystals still limit its performance. Here, the authors overcome this limitation and report the enhanced electronic quality of graphene enabled by tuneable Coulomb screening inside large-angle twisted bilayer and trilayer graphene devices, showing Landau quantization at magnetic fields down to ~5 mT.

Source: Nature Communications

DOI: 10.1038/s41467-025-62492-5

Authors: I. Babich, I. Reznikov, I. Begichev, A. E. Kazantsev, S. Slizovskiy, D. Baranov, M. Šiškins, Z. Zhan, P. A. Pantaleon, M. Trushin, J. Zhao, S. Grebenchuk, K. S. Novoselov, K. Watanabe, T. Taniguchi, V. I. Fal’ko, A. Principi, A. I. Berdyugin

Institutions: National University of Singapore, Institute for Functional Intelligent Materials, University of Manchester, IMDEA Nanoscience, National Institute for Materials Science

Language: English

Topic: Graphene research and applications

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $6,990

Funders: Leverhulme Trust, European Commission, National Research Foundation, Agency for Science, Technology and Research, National Research Foundation Singapore, Ministry of Education, Culture, Sports, Science and Technology, Engineering and Physical Sciences Research Council, Japan Society for the Promotion of Science, Agencia Estatal de Investigación, Core Research for Evolutional Science and Technology

OpenAlex ID: W4413107650