Unconventional ferroelectricity in half-filling states of antiparallel stacking of twisted WSe<sub>2</sub>

Abstract

<p indent="0mm">We report on emergence of an abnormal electronic polarization in twisted double bilayer WSe₂ in antiparallel interface stacking geometry, where local centrosymmetry of atomic registries at the twist interface does not favor the spontaneous electronic polarizations as recently observed in the parallel interface stacking geometry. The unconventional ferroelectric behaviors probed by electronic transport measurement occur at half filling insulating states at <sc>1.5 K</sc> and gradually disappear at about <sc>40 K.</sc> Single band Hubbard model based on the triangular moiré lattice and the interlayer charge transfer controlled by insulating phase transition are proposed to interpret the formation of electronic polarization states near half filling in twisted WSe₂ devices. Our work highlights the prominent role of many-body electronic interaction in fostering novel quantum states in moiré-structured systems.