Abstract

Interfacial ferroelectricity emerges in heterostructures consisting of non-polar van der Waals layers, greatly expanding the scope of two dimensional ferroelectrics. In particular, the unconventional moiré ferroelectricity observed in bilayer graphene/boron nitride heterostructures exhibits promising functionalities with topological current, superconductivity and synaptic responses. However, the debate about its mechanism – correlation driven charge transfer between two graphene layers – limits device reproducibility and hence large-scale production. Here by designing a single-layer graphene encapsulated by lattice-mismatched WSe2, we identify the ferroelectricity as stemming from – instead of graphene moiré bands – the particular BN, where interfacial sliding ferroelectricity must play a role. With similar structures, multilayer twisted MoS₂ is found to reproduce the ferroelectricity. The key is a conductive moiré ferroelectric, where the screened gate and the pinned domain wall together result in unchanged electronic states, i.e. anomalous screening. The intimate connection to interfacial sliding ferroelectricity thus provides advantages of diverse choices of constituent materials and robust polarization switching while preserving the unique anomalous screening, paving the way to reproducible and reliable memory-based devices in artificial intelligence.

Abstract

Interfacial ferroelectricity emerges in heterostructures consisting of non-polar van der Waals layers, greatly expanding the scope of two dimensional ferroelectrics. In particular, the unconventional moiré ferroelectricity observed in bilayer graphene/boron nitride heterostructures exhibits promising functionalities with topological current, superconductivity and synaptic responses. However, the debate about its mechanism – correlation driven charge transfer between two graphene layers – limits device reproducibility and hence large-scale production. Here by designing a single-layer graphene encapsulated by lattice-mismatched WSe2, we identify the ferroelectricity as stemming from – instead of graphene moiré bands – the particular BN, where interfacial sliding ferroelectricity must play a role. With similar structures, multilayer twisted MoS₂ is found to reproduce the ferroelectricity. The key is a conductive moiré ferroelectric, where the screened gate and the pinned domain wall together result in unchanged electronic states, i.e. anomalous screening. The intimate connection to interfacial sliding ferroelectricity thus provides advantages of diverse choices of constituent materials and robust polarization switching while preserving the unique anomalous screening, paving the way to reproducible and reliable memory-based devices in artificial intelligence.

Abstract

Interfacial ferroelectricity emerges in heterostructures consisting of non-polar van der Waals layers, greatly expanding the scope of two dimensional ferroelectrics. In particular, the unconventional moiré ferroelectricity observed in bilayer graphene/boron nitride heterostructures exhibits promising functionalities with topological current, superconductivity and synaptic responses. However, the debate about its mechanism – correlation driven charge transfer between two graphene layers – limits device reproducibility and hence large-scale production. Here by designing a single-layer graphene encapsulated by lattice-mismatched WSe2, we identify the ferroelectricity as stemming from – instead of graphene moiré bands – the particular BN, where interfacial sliding ferroelectricity must play a role. With similar structures, multilayer twisted MoS₂ is found to reproduce the ferroelectricity. The key is a conductive moiré ferroelectric, where the screened gate and the pinned domain wall together result in unchanged electronic states, i.e. anomalous screening. The intimate connection to interfacial sliding ferroelectricity thus provides advantages of diverse choices of constituent materials and robust polarization switching while preserving the unique anomalous screening, paving the way to reproducible and reliable memory-based devices in artificial intelligence.

Abstract

Interfacial ferroelectricity emerges in heterostructures consisting of non-polar van der Waals layers, greatly expanding the scope of two dimensional ferroelectrics. In particular, the unconventional moiré ferroelectricity observed in bilayer graphene/boron nitride heterostructures exhibits promising functionalities with topological current, superconductivity and synaptic responses. However, the debate about its mechanism – correlation driven charge transfer between two graphene layers – limits device reproducibility and hence large-scale production. Here by designing a single-layer graphene encapsulated by lattice-mismatched WSe2, we identify the ferroelectricity as stemming from – instead of graphene moiré bands – the particular BN, where interfacial sliding ferroelectricity must play a role. With similar structures, multilayer twisted MoS₂ is found to reproduce the ferroelectricity. The key is a conductive moiré ferroelectric, where the screened gate and the pinned domain wall together result in unchanged electronic states, i.e. anomalous screening. The intimate connection to interfacial sliding ferroelectricity thus provides advantages of diverse choices of constituent materials and robust polarization switching while preserving the unique anomalous screening, paving the way to reproducible and reliable memory-based devices in artificial intelligence.