This study investigates the nanoscale conductivity of encapsulated monolayer graphene at temperatures down to 5 K and magnetic fields of up to 1 T. We use the scattering-type scanning near-field optical microscopy (s-SNOM) technique to probe magnetic-field-dependent responses from graphene close to charge neutrality in the terahertz spectral region. We observe the near-perfect high-q reflector behavior of graphene but with subtle changes by the presence of magnetic fields. Measurements align with calculations of the magneto-optical conductivity and the near-field spectroscopic contrast that describes the field-tunable cyclotron resonance of Dirac fermions. Our result provides an initial step toward understanding temperature and magnetic-field effects on nanoscale terahertz transport in two-dimensional quantum materials.
@article{arxiv.2604.22940,
title = {Terahertz magneto-nanoscopy of encapsulated monolayer graphene},
author = {Richard H. J. Kim and Sunwoong Yang and Taehoon Kim and Samuel J. Haeuser and Joong-Mok Park and Randall K. Chan and Thomas Koschny and Young-Mi Bahk and Sung Ju Hong and Jigang Wang},
journal= {arXiv preprint arXiv:2604.22940},
year = {2026}
}