Light: Science & Applications (Jul 2023)

Experimental realization of chiral Landau levels in two-dimensional Dirac cone systems with inhomogeneous effective mass

  • Hongwei Jia,
  • Mudi Wang,
  • Shaojie Ma,
  • Ruo-Yang Zhang,
  • Jing Hu,
  • Dongyang Wang,
  • Che Ting Chan

DOI
https://doi.org/10.1038/s41377-023-01209-z
Journal volume & issue
Vol. 12, no. 1
pp. 1 – 7

Abstract

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Abstract Chiral zeroth Landau levels are topologically protected bulk states. In particle physics and condensed matter physics, the chiral zeroth Landau level plays a significant role in breaking chiral symmetry and gives rise to the chiral anomaly. Previous experimental works on such chiral Landau levels are mainly based on three-dimensional Weyl degeneracies coupled with axial magnetic fields. Their realizations using two-dimensional Dirac point systems, being more promising for future applications, were never experimentally realized before. Here we propose an experimental scheme for realizing chiral Landau levels in a two-dimensional photonic system. By introducing an inhomogeneous effective mass through breaking local parity-inversion symmetries, a synthetic in-plane magnetic field is generated and coupled with the Dirac quasi-particles. Consequently, the zeroth-order chiral Landau levels can be induced, and the one-way propagation characteristics are experimentally observed. In addition, the robust transport of the chiral zeroth mode against defects in the system is also experimentally tested. Our system provides a new pathway for the realization of chiral Landau levels in two-dimensional Dirac cone systems, and may potentially be applied in device designs utilizing the chiral response and transport robustness.