Real higher-order Weyl photonic crystal

Area of Science:

• Condensed Matter Physics
• Topological Materials
• Photonic Crystals

Background:

• Higher-order Weyl semimetals combine Weyl point properties with higher-order topology.
• Previous demonstrations were limited to phononics and circuits.

Purpose of the Study:

• To experimentally discover a higher-order Weyl semimetal phase in a three-dimensional photonic crystal.
• To investigate the concurrence of surface and hinge Fermi arcs and their topological origins.

Main Methods:

• Fabrication and characterization of a three-dimensional photonic crystal.
• Analysis of bulk and surface/hinge states using topological invariants.
• Investigation of the projected 2D subsystem's topological class.

Main Results:

• Experimental realization of a real higher-order Weyl photonic crystal.
• Observation of coexisting surface and hinge Fermi arcs.
• Identification of a real Chern insulator phase in the projected 2D subsystem, belonging to the Stiefel-Whitney class.

Conclusions:

• The discovered real higher-order Weyl photonic crystal provides a novel platform for topological physics.
• This work expands the understanding of higher-order topology and real topological insulators.
• Potential for exploring new applications in photonic devices and topological quantum technologies.