Graphene superlattice study reports gate-tunable spin polarization

Researchers have reported a new graphene spintronic effect that can be controlled electrically in superlattice devices, a result that sharpens one of the field’s most closely watched goals: moving spin-based transport from a laboratory curiosity toward usable low-power components.

Electric control sharpens the graphene spin signal

The study, published on April 15, 2026, in Nature Communications, finds that cobalt contacts can induce magnetic proximity effects in graphene and that the resulting spin-resolved transport can be tuned with a gate voltage near the charge neutrality point. In the device structures tested, the nonlocal spin signal inverted as carrier density changed, indicating that proximity-induced spin splitting was governing the transport response.

The authors report similar inversions at satellite neutrality points in graphene-boron nitride aligned superlattices, extending the effect beyond a single band configuration. That matters because superlattices reshape graphene’s electronic landscape and can expose behavior that is not visible in ordinary devices.

Bilayer devices reached nearly 50% spin polarization

The most striking result came from a bilayer graphene superlattice device, where the team observed spin polarizations approaching 50% and nonlocal spin resistances above 300 ohms. The paper says those values were nearly two orders of magnitude larger than measurements taken away from charge neutrality.

Because the bilayer structure also opens a bandgap, it appears to provide more selective spin filtering than the single-layer cases. The work suggests that carefully engineered two-dimensional stacks may offer a practical route to stronger spin control than plain graphene devices have delivered so far.

Why the result matters for 2D materials engineering

Graphene has remained central to two-dimensional materials research because it is fast, chemically robust and compatible with layered heterostructure fabrication, but it has long been difficult to turn those traits into a device that also manipulates spin efficiently. This result pushes in that direction by showing that spin polarization can be modulated by electrostatics rather than fixed magnetic structures alone.

If the effect can be reproduced in more device-friendly formats, it could inform lower-power spintronic logic or sensing architectures built from van der Waals materials. For now, the significance is narrower but concrete: the study gives a clearer experimental path for using graphene superlattices as electrically adjustable spin filters.