Classification of Dirac points with higher-order Fermi arcs

Dirac semimetals lack stable surface Fermi arcs. However, they can exhibit a bulk-hinge correspondence: when terminated in a rod geometry, zero energy arclike states appear on the hinges connecting the projections of the bulk Dirac points. In this work, the authors derive symmetry indicators that determine the existence of higher-order Fermi arcs for general symmetry groups. The results show that Dirac points with linear dispersion in all directions always exhibit higher-order Fermi arcs, while Dirac points with quadratic dispersion in two directions do not.