Programmable electric hysteresis in graphite/MoS₂ heterojunctions through twisting.

Abstract

Van der Waals devices have recently been shown to enable remarkable field-effect control over electronic orders, including sliding ferroelectricity. In this work, we report robust electric hysteresis in graphite/MoS₂ heterojunction devices. The hysteretic behavior is programmable via interlayer twisting, with the memory window sharply decreasing near 30°, confirming strong angle-dependent modulation. Owing to the superlubric nature of the interface, such manipulation can be performed rapidly and with minimal energy cost. The underlying mechanism is further supported by the observation of a finite out-of-plane piezoelectric response in the graphite/MoS₂ heterojunction, with an effective piezoelectric coefficient of d₃₃ = 3.8 pm/V. Density functional theory calculations reveal that the electric response originates from a combination of interfacial charge transfer and moiré potential effects, without requiring interlayer sliding to explain the observed hysteresis. This work shows that adjusting the twist-angle in heterojunctions can control ferroelectric and piezoelectric properties, enabling better nanoelectronic devices.