A collaborative team of researchers led by physicists from the Slovak Academy of Sciences has successfully theorized a groundbreaking method for controlling spin currents in graphene. By coupling graphene with a ferroelectric monolayer of In2Se3, they demonstrated that ferroelectric switching can effectively reverse the direction of spin currents. This discovery, published on November 14, 2025, in the journal Materials Futures, presents a significant step toward the development of energy-efficient, nonvolatile spintronic devices.
Over the past twenty years, spintronics has emerged as a promising area within nanoelectronics, aiming to leverage the intrinsic angular momentum, or spin, of electrons for information processing. In contrast to traditional charge-based electronics, spin-based systems offer the potential for significantly reduced power consumption, lower heat generation, and faster operational speeds. Nonetheless, a critical challenge remains: achieving precise electrical control over spin currents without the use of external magnetic fields.
The researchers focused on the potential of graphene, known for its exceptional electronic mobility and long spin-relaxation times. While graphene is a prime candidate for spintronics, its limited intrinsic spin-orbit coupling has hindered direct spin control. To address this limitation, scientists have explored van der Waals heterostructures, which involve stacking graphene with other two-dimensional (2D) materials to induce new functionalities through proximity effects.
Integrating ferroelectric materials that exhibit spontaneous electric polarization with graphene can enable a new method of spin control. When a ferroelectric material contacts graphene, its electric dipole can break the inversion symmetry at the interface, allowing for potential electric switching of spin orientation. The research team introduced a novel graphene/In2Se3 heterostructure platform that harnesses the ferroelectric polarization of In2Se3 to modulate the spin-orbit coupling in graphene.
Through first-principles calculations and tight-binding simulations, the researchers revealed that flipping the polarization direction of In2Se3 reverses the sign of the Rashba-Edelstein effect. This phenomenon enables the switching of spin textures and the direction of spin currents, all without the requirement for external magnetic fields. The effects are achieved with minimal power once the polarization is set.
Key Findings and Implications for Future Technology
The research team examined graphene/In2Se3 heterostructures under two configurations: a perfectly aligned (0°) interface and a twisted geometry (17.5°). Their electronic structure calculations indicated that reversing the ferroelectric polarization of the In2Se3 monolayer acts as an electrical “chirality switch” for spin currents in graphene. In the aligned configuration, the system demonstrated a conventional Rashba-Edelstein effect, where an applied charge current creates a transverse spin accumulation aligned with the ferroelectric polarization. In the twisted configuration, the system exhibited an unconventional Rashba-Edelstein effect, leading to a nearly collinear relationship between the spin current and charge flow due to the emergence of a radial Rashba field—an innovative phenomenon not previously observed in planar graphene systems.
The findings lay a theoretical foundation for the realization of graphene-based spin transistors that can be controlled through ferroelectric switching. This advancement could pave the way for next-generation spin logic and memory devices characterized by low energy consumption and high-speed performance. The study emphasizes the exciting potential of integrating two-dimensional ferroelectric materials with graphene to unlock new functionalities in spintronics.
Future research efforts should prioritize the experimental validation of these theoretical results, ultimately aiming to create electrically controlled, non-volatile spintronic devices that meet the demands of modern technology.
