Fermi-Arc-Induced Vortex Structure in Weyl Beam Shifts.

Area of Science:

• Condensed Matter Physics
• Topological Materials Science
• Photonics and Optics

Background:

• Periodic media exhibit coupled bulk and topological surface states, often studied independently.
• Weyl media possess unique topological properties, including Fermi arc surface states.
• Beam reflection phenomena like Goos-Hänchen and Imbert-Fedorov shifts are sensitive to boundary conditions.

Purpose of the Study:

• To investigate the interplay between bulk geometrical effects and topological surface states in Weyl media.
• To demonstrate a novel method for probing topological characteristics using reflected beam trajectories.
• To analyze the displacement of reflected beams at the interface between a Weyl medium and a gapped medium.

Main Methods:

• Theoretical analysis of beam reflection at the interface of a Weyl medium and a gapped medium.
• Investigation of the trajectory shifts of reflected beams.
• Characterization of the resulting half-vortex structure in the surface momentum space.

Main Results:

• Reflected beams exhibit displacements influenced by both bulk geometry and Fermi arc surface states.
• A unique half-vortex is formed in the surface momentum space of the reflected beam.
• The magnitude of the displacement scales with an inverse square root dependence near the Weyl cone touching point.

Conclusions:

• The observed half-vortex displacement provides a direct link between bulk transport and topological surface states.
• This phenomenon offers a new experimental pathway to probe the topological characteristics of Weyl media.
• Bulk transport measurements can be utilized to characterize topological properties in periodic materials.