Quantum materials are characterized by electromagnetic responses intrinsically linked to the geometry and topology of electronic wavefunctions, encoded in the quantum metric and Berry curvature. Whereas Berry curvature-mediated transport effects have been identified in several magnetic and nonmagnetic systems, quantum metric-induced transport phenomena remain limited to topological antiferromagnets. Here we show that spin-momentum locking -- a general characteristic of the electronic states at surfaces and interfaces of spin-orbit coupled materials -- leads to a finite quantum metric. This metric activates a nonlinear in-plane magnetoresistance that we measure and electrically control in 111-oriented LaAlO3/SrTiO3 interfaces. These findings demonstrate the existence of quantum metric effects in a vast class of materials and enable previously unexplored strategies to design functionalities based on quantum geometry.
@article{arxiv.2407.06659,
title = {The quantum metric of electrons with spin-momentum locking},
author = {Giacomo Sala and Maria Teresa Mercaldo and Klevis Domi and Stefano Gariglio and Mario Cuoco and Carmine Ortix and Andrea D. Caviglia},
journal= {arXiv preprint arXiv:2407.06659},
year = {2025}
}