Weyl Orbit: Fermi Arc Quantum Oscillations

Weyl semimetals host topologically protected surface states called Fermi arcs — open contours connecting projections of bulk Weyl nodes with opposite chirality. Under a magnetic field B∥z, electrons can complete orbits by traversing a Fermi arc on the top surface, tunneling through the bulk, traversing the arc on the bottom surface, and tunneling back. These "Weyl orbits" produce quantum oscillations with frequency F = (ℏ/2πe)(k₀·d + A_bulk), where k₀ is node separation, d is slab thickness, and A_bulk is the bulk pocket area. The oscillation period 1/B carries topological information about the arc connectivity.