Terahertz magneto-nanoscopy of encapsulated monolayer graphene

Richard H. J. Kim; Sunwoong Yang; Taehoon Kim; Samuel J. Haeuser; Joong-Mok Park; Randall K. Chan; Thomas Koschny; Young-Mi Bahk; Sung Ju Hong; Jigang Wang

doi:10.1063/5.0310548

arXiv · 2604.22940

Terahertz magneto-nanoscopy of encapsulated monolayer graphene

Richard H. J. Kim·Sunwoong Yang·Taehoon Kim·Samuel J. Haeuser·Joong-Mok Park·Randall K. Chan·Thomas Koschny·Young-Mi Bahk·Sung Ju Hong·Jigang Wang

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Abstract

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.

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Richard H. J. Kim, Sunwoong Yang, Taehoon Kim, Samuel J. Haeuser, Joong-Mok Park, Randall K. Chan, Thomas Koschny, Young-Mi Bahk, Sung Ju Hong, Jigang Wang. 2026-04-24. Terahertz magneto-nanoscopy of encapsulated monolayer graphene. https://doi.org/10.1063/5.0310548

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