Ferroelectric hysteresis in singly aligned graphene-hBN moir\'e superlattices

Ferroelectric materials have the unique ability to maintain an electric polarization which can be reversed under an external applied electric field. This property makes them valuable for applications such as non-volatile random-access memories, transducers, actuators and electro optic modulators. Recently, emergent unconventional ferroelectricity has been demonstrated in moir\'e superlattices of bilayer graphene and hexagonal boron nitride (hBN) hosting non centrosymmetric stacking order. Whether this phenomenon is also present in noncentrosymmetric single layer graphene (SLG)-hBN moir\'e superlattices is still under debate. Here we demonstrate a ferroelectric response in an SLG-hBN moir\'e superlattice. Through Hall measurements, we pinpoint the origin of the hysteretic behavior to abnormal charge screening due to the moir\'e superlattice band and estimate the spontaneous polarization magnitude in the moir\'e superlattice structure. Temperature dependent measurements confirm that the hysteretic behavior persists from 2K up to room temperature, opening opportunities for high-mobility, ultrathin non-volatile devices