Coexistence of photonic Weyl points and nodal rings in topological gyroelectric continuum media

In recent studies, it has been demonstrated that topological systems can host a variety of topological semimetal phases, including Weyl points, nodal lines, rings, chains, and nodal surfaces, offering diverse opportunities for exploring novel physical phenomena. However, previous studies mainly focused on exploring a single type of band degeneracy in topological systems. In this work, we demonstrate the coexistence of zero-dimensional Weyl points and one-dimensional nodal rings in the topological gyroelectric continuum media. Through rigorous theoretical analysis, we show a comprehensive depiction of topological phase diagrams of these band degenerates in the continuum media and give the critical conditions of the coexistence of Weyl points and nodal rings. Remarkably, the size of the nodal rings in three-dimensional momentum space that varies with the gyroelectric parameter ωₑ and reveals the magnetic field strength can be regarded as the degree of freedom of control band degeneracies. The topologically protected Fermi arc surface states arise when the gyroelectric continuum media are in direct touch with the vacuum state owing to the bulk boundary correspondence. Moreover, a type of multichannel and reconfigurable photonic topological pathway is realized using the unidirectional Fermi arc surface states. This study establishes a flexible framework for examining the interactions between Weyl semimetals and nodal semimetals, paving the way for the development of innovative photonic topological devices with promising applications.