Researchers at Tohoku University and Japan Atomic Energy Agency (JAEA) report controlling the quantum-geometric nonlinear Hall (QgNLH) state with electric current for the first time, a feat detailed in the journal Newton on November 4, 2026. The team achieved this by exploiting the connection between spin structure and the QgNLH state within an electrically switchable chiral antiferromagnet, opening a potential pathway for tunable devices using quantum-geometric effects. “We are able to realize on-demand electrical manipulation of the QgNLH state under different external conditions,” noted Tomohiro Uchimura, the paper’s leading author, suggesting new possibilities for nonlinear signal processing.
Quantum-Geometric Nonlinear Hall State Observed in Mn3Sn
Unlike previous interpretations of quantum geometry as a static material property, the team demonstrated active manipulation of the nonlinear electronic responses through electrical control of the material’s magnetic order. This approach may enable electric-current-tunable nonlinear devices, potentially benefiting magnetoresistive random access memory (MRAM) with improved energy efficiency and speed. The ability to deterministically switch and fluctuate the QgNLH state represents an advancement in quantum materials research; the team achieved this under finite and zero bias magnetic fields, respectively.
This electrical switching capability distinguishes this work from earlier studies, which primarily focused on observing the QgNLH state as a fixed characteristic of materials. Researchers verified the quantum-geometric origin of the observed effect by reversing the spin structure of Mn3Sn, directly revealing the connection between the QgNLH state and magnetic order.
The experimental setup involved a Hall bar device fabricated from Mn3Sn, where the nonlinear Hall voltage exhibited a cubic relationship with the applied current. This observation of a third-order nonlinear Hall effect at room temperature further validates the quantum-geometric origin of the phenomenon. The team’s findings suggest a pathway toward developing devices like frequency multiplexers and rectifiers, using the unique properties of the QgNLH state for advanced signal processing applications. The potential for integrating spintronic methods into these devices offers a promising route for creating faster and more energy-efficient technologies.
We are able to realize on-demand electrical manipulation of the QgNLH state under different external conditions.
Tomohiro Uchimura, leading author of the paper
The team achieved this control by using spin-orbit torque, induced by electric current flowing into an adjacent heavy metal layer, to switch the spin structure of the Mn3Sn film. This switching directly altered the third-order nonlinear Hall response, confirming the link between magnetic order and the QgNLH state.
Instead of treating quantum geometry as a fixed property of the material, we showed how the nonlinear electronic responses from quantum geometry can be actively manipulated by electrically controlling the material’s magnetic order.
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