Electric control of quantum-geometric nonlinear Hall state achieved

Researchers at Tohoku University and the Japan Atomic Energy Agency (JAEA) have demonstrated electric control of the quantum-geometric nonlinear Hall state using electric current for the first time. They achieved this in the chiral antiferromagnet Mn₃Sn, where the QgNLH state was observed at room temperature as a third-order nonlinear Hall effect, with the nonlinear voltage proportional to the cube of the applied current. The study was published in the Cell Press journal Newton on November 4, 2026.

This breakthrough connects quantum geometry, nonlinear electronics, and spintronics. It shows that quantum geometric effects, previously considered a fixed material property, can be actively manipulated. The research team investigated epitaxial thin films of Mn₃Sn and used spintronic approaches to electrically control the magnetic order. This was done via spin-orbit torque from an adjacent heavy metal layer.

Reversible switching via spin structure manipulation

The quantum-geometric nonlinear Hall state was reversibly switched by altering the spin structure of Mn₃Sn. This revealed the direct interplay between the QgNLH state and the material's magnetic order. The researchers switched the sign of the third-order nonlinear Hall response by applying current pulses with opposite polarities. The effect's quantum-geometric origin was confirmed through this reversible control.

Spintronic electrical control mechanism

The electrical manipulation was made possible by spintronic methods. Spin-orbit torque from a heavy metal layer adjacent to the Mn₃Sn film enabled the precise control of the magnetic order needed to toggle the QgNLH state. This approach leverages the inherent advantages of magnetoresistive random access memory (MRAM) technologies, such as energy efficiency and speed.

Quantum geometry manipulation potential

The achievements offer a potential approach for developing electrically tunable devices that use quantum-geometric effects to perform nonlinear signal processing functions. Corresponding authors Jiahao Han and Shunsuke Fukami explained that the approach enables electric-current-tunable nonlinear devices such as frequency multiplexers and rectifiers. Lead author Tomohiro Uchimura stated that deterministic switching and fluctuation of the QgNLH state can be achieved under finite and zero bias magnetic fields, respectively. "We are able to realize on-demand electrical manipulation of the QgNLH state under different external conditions," Uchimura said.