Quantum Transport Spectroscopy of Pseudomagnetic Field in Graphene

Nonuniform strain in graphene acts as a valley-dependent gauge field, generating pseudomagnetic fields (PMFs) that mimic real magnetic fields while preserving global time-reversal symmetry. While such fields have been visualized locally, their quantitative detection via macroscopic transport has remained elusive. Here, we show that graphene exhibits distinct beating patterns in Shubnikov-de Haas oscillations arising from valley-resolved Landau quantization under different effective magnetic fields. Systematic analysis of the beating nodes reveals universal quadratic and linear scaling of the carrier density and Landau level filling factor with magnetic field, enabling the extraction of PMFs of order millitesla. Our results establish quantum oscillation spectroscopy as a robust transport probe of strain-induced gauge fields in Dirac materials and open avenues for mechanically tunable valleytronic and straintronic devices.