Unconventional ferroelectricity in half-filling states of antiparallel stacking of twisted WSe2

TL;DR

This study reveals unconventional ferroelectricity in twisted WSe2 with antiparallel stacking, driven by many-body electronic interactions, and characterized by electronic polarization emerging at half-filling states and disappearing around 40 K.

Contribution

It demonstrates the emergence of electronic ferroelectricity in antiparallel twisted WSe2, highlighting the role of many-body interactions in moiré systems, a phenomenon not observed in parallel stacking.

Findings

Electronic polarization appears at half-filling states.

Ferroelectric behavior diminishes above 40 K.

Many-body interactions are crucial for this phenomenon.

Abstract

Abstract: 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 1.5 K and gradually disappear at about 40 K. Single band Hubbard model based on the triangular moir\'e 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 moir\'e-structured systems.