Fig. 2: Twisted bi-block Weyl metamaterials: Round-trip eigen phases and twisted Fermi arcs.
From: Twisted photonic Weyl meta-crystals and aperiodic Fermi arc scattering
a Round-trip eigen phases and planar waveguide consisting of the top/bottom Weyl metamaterial and the middle spacer layer. b Interface Fermi arcs when \(\theta=30^\circ\). c The round-trip eigen phase exhibits double-sheet Riemann surface structure. d The zoom-in view of the double-sheet Riemann surface structure in (c) around one Weyl point as encircled in (b). e The round-trip eigen phases around one Weyl point as indicated by the dashed circle in (b), which also corresponds to the helical boundary in (d). The horizontal dashed line denotes the guided mode condition \(\varphi={\varphi }^{I}+{\varphi }^{{II}}=2n{{{{{\rm{\pi }}}}}}\). f Torus knots built by mapping the round-trip eigen phases onto a torus.
