Soliton Disentangling and Ferroelectric Hysteresis in Bilayer MoS2 Nanostructures with Reconstructed Moiré Superlattices

Abstract

Emergent interfacial ferroelectricity has been surprisingly found in spatial inversion symmetry broken moiré systems, such as rhombohedral-stacked bilayer transition metal dichalcogenides (TMDs). However, the lattice dynamics of nanoscale polarization switching and ferroelectric hysteresis remain unclear. Here we report on the observation of phonon splitting of soliton networks in bilayer MoS2 nanostructures with reconstructed moiré superlattices. By tuning a perpendicular displacement field, the interval of phonon splitting exhibits a distinct hysteresis behavior, which arises from solitons disentangling and lattice viscosity. Moreover, we demonstrate a proof-of-principle moiré ferroelectric tunneling junction. Our work presents a potential pathway for future moiré-based nanodevices.