Built-in Bernal gap in large-angle-twisted monolayer-bilayer graphene

Alex Boschi, Zewdu M. Gebeyehu, Sergey Slizovskiy, Vaidotas Mišeikis, Stiven Forti, Antonio Rossi, Kenji Watanabe, Takashi Taniguchi, Fabio Beltram, Vladimir I. Fal'ko, Camilla Coletti, Sergio Pezzini

Research output: Contribution to journalArticlepeer-review

Abstract

Atomically thin materials offer multiple opportunities for layer-by-layer control of their electronic properties. While monolayer graphene (MLG) is a zero-gap system, Bernal-stacked bilayer graphene (BLG) acquires a finite band gap when the symmetry between the layers’ potential energy is broken, usually, via a displacement electric field applied in double-gate devices. Here, we introduce a twistronic stack comprising both MLG and BLG, synthesized via chemical vapor deposition, showing a Bernal gap in the absence of external fields. Although a large (~30°) twist angle decouples the MLG and BLG electronic bands near Fermi level, proximity-induced energy shifts in the outermost layers result in a built-in asymmetry, which requires a displacement field of 0.14 V/nm to be compensated. The latter corresponds to a ~10 meV intrinsic BLG gap, a value confirmed by our thermal-activation measurements. The present results highlight the role of structural asymmetry and encapsulating environment, expanding the engineering toolbox for monolithically-grown graphene multilayers.
Original languageEnglish
Article number391
JournalCommunications physics
Volume7
DOIs
Publication statusPublished - 1 Dec 2024

Research Beacons, Institutes and Platforms

  • National Graphene Institute

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