Séminaire Matériaux Quantiques : jeudi 19 mars 2026 à 14h00
Rebeca Ribeiro (C2N, Paris-Saclay)
Titre : Twist-Angle-Controlled Anomalous Gating in Bilayer Graphene/BN Heterostructures
Institut Néel, Salle K223 (Salle Rémy Lemaire)
Résumé : Anomalous gating effects—such as gate ineffectiveness and pronounced hysteresis—have been observed in graphene-based systems encapsulated in boron nitride (BN) and linked to a possible ferroelectric state. However, their origin, stability, and reproducibility remain under debate. During this talk, I will present charge transport experiments in dual-gated, dynamically rotatable van der Waals heterostructures based on bilayer graphene encapsulated in BN. Remarkably, the angular degree of freedom acts as an ON/OFF switch for the anomalous gating response. We show that the angular alignment between the two BN layers is the key parameter governing these effects. Both gate ineffectiveness and hysteresis are highly sensitive to small angular changes, and they clearly change in behavior, which we classify into three distinct regimes.
