Electric Field Tunable Interlayer Sliding Ferroelectricity in 2H-Stacked Multilayer WSe2

Abstract

Ferroelectricity in two-dimensional (2D) materials has strong potential for the development of ultrathin, low-power memory devices. However, most 2D ferroelectric systems reported to date rely on moiré superlattices or structural asymmetry, such as rhombohedral stacking, limiting their scalability and fabrication yield. Here, we report emergent ferroelectric switching in hexagonal (2H)-stacked multilayer Tungsten diselenide (WSe₂) heterostructures. In devices composed of 2L or thicker WSe₂ and graphene electrical sensors, four-terminal resistance measurements reveal clear hysteresis and switching behavior, which remain stable over tens of repeated cycles. In particular, applying a bottom gate voltage to modulate the external electric field led to an increase in both the relaxation time and polarization magnitude. Density functional theory (DFT) calculations show that although ideal 2H-stacked multilayer WSe₂ preserves mirror or inversion symmetry, an applied electric field induces interlayer sliding toward metastable states that break the symmetry. The calculated polarization is in good agreement with the experimental values inferred from Hall carrier density measurements. Our findings deepen the understanding of sliding ferroelectricity in naturally stacked 2H-stacked transition metal dichalcogenides (TMDs) with implications for the design of scalable ferroelectric devices that do not require artificial symmetry breaking.

Keywords: 2H-stacked multilayer WSe2; electric field controllable; electrical polarization; ferroelectric memory; graphene sensor; interlayer sliding ferroelectricity.