Owing to the chirality of Weyl nodes, the Weyl systems can support one-way chiral zero modes under a strong magnetic field, which leads to nonconservation of chiral currents—the so-called chiral anomaly. Although promising for robust transport of optical information, the zero chiral bulk modes have not been observed in photonics. Here we design an inhomogeneous Weyl metamaterial in which a gauge field is generated for the Weyl nodes by engineering the individual unit cells. We experimentally confirm the presence of the gauge field and observe the zero-order chiral Landau level with one-way propagation. Without breaking the time-reversal symmetry, our system provides a route for designing an artificial magnetic field in three-dimensional photonic Weyl systems and may have potential for device applications in photonics.
Motivated by recent experiments on FeTe1−xSex, we construct an explicit minimal model of an iron-based superconductor with band inversion at the Z point and non-topological bulk s± pairing. While there has been considerable interest in Majorana zero modes localized at vortices in such systems, we find that our model -without any vortices -intrinsically supports 1D helical Majorana modes localized at the hinges between (001) and (100) or (010) surfaces, suggesting that this is a viable platform for observing "higher-order" topological superconductivity. We provide a general theory for these hinge modes and discuss their stability and experimental manifestation. Our work indicates the possible experimental observability of hinge Majoranas in iron-based topological superconductors.arXiv:1812.10493v2 [cond-mat.supr-con]
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.