Three-dimensional photonic quantum Hall effect of Fermi arcs

Area of Science:

• Condensed Matter Physics
• Topological Materials
• Photonic Crystals

Background:

• The three-dimensional quantum Hall effect (3D QHE) in topological semimetals is a significant advancement in Hall physics.
• A key characteristic, one-sided chiral hinge states of Fermi arcs, has remained experimentally unobserved.
• Topological semimetals exhibit unique electronic properties with potential applications in quantum technologies.

Purpose of the Study:

• To experimentally realize and observe the 3D quantum Hall effect (QHE) of Fermi arcs in a photonic system.
• To demonstrate the existence and characteristics of one-sided chiral hinge states in a photonic crystal.
• To explore the potential of photonic systems for studying fundamental quantum phenomena and developing novel devices.

Main Methods:

• Fabrication of an inhomogeneous magnetic Weyl photonic crystal.
• Application of a pseudomagnetic field (PMF) to break time-reversal symmetry.
• Experimental observation and characterization of bulk and surface states using techniques sensitive to Landau quantization.

Main Results:

• Successful photonic realization of 3D QHE of Fermi arcs.
• Direct observation of one-sided chiral hinge states localized on specific edges of the photonic crystal.
• Demonstration that the pseudomagnetic field quantizes both bulk and Fermi arc surface states into Landau plateaus.
• Observation of tunable switching of chiral hinge states by reversing the pseudomagnetic field.

Conclusions:

• The study provides the first experimental evidence of 3D QHE of Fermi arcs in a photonic system.
• The observed one-sided chiral hinge states confirm a key prediction of 3D QHE theory.
• This work establishes a novel platform for exploring 3D quantum Hall physics and designing robust photonic devices.