Higher-orderWeyl superconductors with anisotropic Weyl-point connectivity

Weyl superconductors feature Weyl points at zero energy in the three-dimensional Brillouin zone and arc states that connect the projections of these Weyl points on the surface. We report that higher-order Weyl superconductors can be realized in odd-parity topological superconductors with time-reversal symmetry being broken by periodic driving. Different from conventional Weyl points, the higher-order Weyl points in the bulk separate 2D first- and second-order topological phases, while on the surface, their projections are connected not only by conventional surface Majorana arcs but also by hinge Majorana arcs. Strikingly, without the protection by a Chern number, the hinge Majorana arcs are anisotropic with respect to surface orientations, forcing a different connectivity of Weyl points for a rotated surface. We identify such anisotropic Weyl-point connectivity as a characteristic feature of higher-order Weyl materials. Moreover, with time-reversal symmetry being broken, the higher-order hinge Majorana arcs are spin polarized, which offers a promising opportunity to observe the anisotropic Weyl-point connectivity with spin-sensitive probes. Besides condensed-matter systems, we provide a feasible experimental setup for realizing our predictions in cold-atom systems.

Automated summary

This study reveals that higher-order Weyl superconductors can be realized in odd-parity topological superconductors with time-reversal symmetry being broken by periodic driving. Unlike traditional Weyl points, the higher-order Weyl points in the bulk separate different topological phases, and their projections on the surface are connected by hinge Majorana arcs. The anisotropic connectivity of hinge Majorana arcs is identified as a characteristic feature of higher-order Weyl materials.