English

Optical control of orbital magnetism in magic angle twisted bilayer graphene

Strongly Correlated Electrons 2025-03-28 v1 Mesoscale and Nanoscale Physics

Abstract

Flat bands in graphene-based moir\'e structures host a wide range of emerging strongly correlated and topological phenomena. Optically probing and controlling them can reveal important information such as symmetry and dynamics, but have so far been challenging due to the small energy gap compared to optical wavelengths. Here, we report near infrared optical control of orbital magnetism and associated anomalous Hall effects (AHE) in a magic angle twisted bilayer graphene (MATBG) on monolayer WSe2_2 device. We show that the properties of the AHE, such as hysteresis and amplitude, can be controlled by light near integer moir\'e fillings, where spontaneous ferromagnetism exists. By modulating the light helicity, we observe periodic modulation of the transverse resistance in a wide range of fillings, indicating light induced orbital magnetization through a large inverse Faraday effect. At the transition between metallic and AHE regimes, we also reveal large and random switching of the Hall resistivity, which are attributed to optical control of percolating cluster of magnetic domains. Our results open the door to optical manipulation of correlation and topology in MATBG and related structures.

Keywords

Cite

@article{arxiv.2503.21750,
  title  = {Optical control of orbital magnetism in magic angle twisted bilayer graphene},
  author = {Eylon Persky and Minhao He and Jiaqi Cai and Takashi Taniguchi and Kenji Watanabe and Xiaodong Xu and Aharon Kapitulnik},
  journal= {arXiv preprint arXiv:2503.21750},
  year   = {2025}
}

Comments

16 pages, 9 figures