Quantum Transport Spectroscopy of Pseudomagnetic Field in Graphene

TL;DR

This study demonstrates that quantum oscillation spectroscopy can quantitatively detect pseudomagnetic fields in graphene caused by nonuniform strain, revealing valley-dependent Landau quantization through characteristic beating patterns in transport measurements.

Contribution

It introduces a macroscopic transport method to measure pseudomagnetic fields in graphene, enabling quantitative analysis of strain-induced gauge fields via quantum oscillations.

Findings

Detection of pseudomagnetic fields as small as a few millitesla.

Universal quadratic and linear scaling laws for Landau level filling.

Observation of valley-resolved Landau quantization in high-mobility graphene.

Abstract

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