Proximity screening greatly enhances electronic quality of graphene

Domaretskiy, Daniil and Wu, Zefei and Nguyen, Van Huy and Hayward, Ned and Babich, Ian and Li, Xiao and Nguyen, Ekaterina and Barrier, Julien and Indykiewicz, Kornelia and Wang, Wendong and Gorbachev, Roman V. and Xin, Na and Watanabe, Kenji and Taniguchi, Takashi and Hague, Lee and Fal’ko, Vladimir I. and Grigorieva, Irina V. and Ponomarenko, Leonid A. and Berdyugin, Alexey I. and Geim, Andre K. (2025) Proximity screening greatly enhances electronic quality of graphene. Nature, 644 (8077). pp. 646-651. ISSN 0028-0836

Abstract

The electronic quality of two-dimensional systems is crucial when exploring quantum transport phenomena. In semiconductor heterostructures, decades of optimization have yielded record-quality two-dimensional gases with transport and quantum mobilities reaching close to 108 and 106 cm2 V−1 s−1, respectively1, 2, 3, 4, 5, 6, 7, 8, 9–10. Although the quality of graphene devices has also been improving, it remains comparatively lower11, 12, 13, 14, 15, 16–17. Here we report a transformative improvement in the electronic quality of graphene by employing graphite gates placed in its immediate proximity, at 1 nm separation. The resulting screening reduces charge inhomogeneity by two orders of magnitude, bringing it down to a few 107 cm−2 and limiting potential fluctuations to less than 1 meV. Quantum mobilities reach 107 cm2 V−1 s−1, surpassing those in the highest-quality semiconductor heterostructures by an order of magnitude, and the transport mobilities match their record9, 10. This quality enables Shubnikov–de Haas oscillations in fields as low as 1 mT and quantum Hall plateaux below 5 mT. Although proximity screening predictably suppresses electron–electron interactions, fractional quantum Hall states remain observable with their energy gaps reduced only by a factor of 3–5 compared with unscreened devices, demonstrating that many-body phenomena at spatial scales shorter than 10 nm remain robust. Our results offer a reliable route to improving electronic quality in graphene and other two-dimensional systems, which should facilitate the exploration of new physics previously obscured by disorder.