Quantum geometry-induced nonlinear magnetotransport in spin-momentum-locked Rashba and Dirac bands

SPICE Workshop on Young Research Leaders Group Workshop: Transport and transfer of angular momentum: magnons, chiral phonons and beyond June 9th - 11th, 2026

Giacomo Sala

The quantum geometrical properties of electronic wavefunctions can drive unique transport phenomena. An archetypal example is the Berry curvature-induced anomalous Hall effect [1]. Beside the Berry curvature, another geometrical structure – the quantum metric – has recently come to the fore as a fundamental ingredient of nonlinear transport [2-3]. However, experimental evidence for quantum metric-driven transport effects remains limited to a handful of materials [4-5]. Here, we predict that spin-momentum-locked bands allow for an intrinsic, time-reversal odd, quantum metric magnetoresistance (QMMR). We show that the QMMR can be probed by nonlinear magnetotransport in Rashba 2D electron gases and in the Dirac surface states of 3D topological insulators, such as the SrTiO₃/LaAlO₃ oxide interface [6] and Sb₂Te₃ thin films [7]. Further, we demonstrate that the quantum metric and QMMR can be controlled in field-effect devices by applying gate voltages. Because the QMMR originates from spin-momentum locking, it provides a new means to probe angular momentum textures in momentum space. Moreover, as the quantum metric can induce nonlinear spin currents and nonlinear spin magnetization, our findings open the door to the nonlinear generation and transport of angular momentum.

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