TY - JOUR
T1 - Built-in Bernal gap in large-angle-twisted monolayer-bilayer graphene
AU - Boschi, Alex
AU - Gebeyehu, Zewdu M.
AU - Slizovskiy, Sergey
AU - Mišeikis, Vaidotas
AU - Forti, Stiven
AU - Rossi, Antonio
AU - Watanabe, Kenji
AU - Taniguchi, Takashi
AU - Beltram, Fabio
AU - Fal'ko, Vladimir I.
AU - Coletti, Camilla
AU - Pezzini, Sergio
PY - 2024/12/1
Y1 - 2024/12/1
N2 - 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.
AB - 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.
U2 - 10.1038/s42005-024-01887-0
DO - 10.1038/s42005-024-01887-0
M3 - Article
SN - 2399-3650
VL - 7
JO - Communications physics
JF - Communications physics
M1 - 391
ER -