Magnetic Weyl Semimetal in K₂Mn₃(AsO₄)₃ with the Minimum Number of Weyl Points

The "hydrogen atom" of magnetic Weyl semimetals, with the minimum number of Weyl points, has received growing attention recently due to the possible presence of Weyl-related phenomena. Here, we propose the ferromagnetic alluaudite-type compound K₂Mn₃(AsO₄)₃ as a promising candidate of "hydrogen atom" of magnetic Weyl semimetal with only a pair of Weyl points around the Fermi level. The Weyl points constrained in the z-direction by the two-fold rotation symmetry around the direction lead to the presence of extremely long Fermi arcs on the yoz surface, which are expected to be easily observed by angle-resolved photoemission spectroscopy experiment. Based on the low-energy effective model of the ferromagnetic K₂Mn₃(AsO₄)₃, we also explore the possible nontrivial superconductor states, giving rise to the discovery of the chiral p-wave and chiral f-wave states etc. Depending on the shape of the Fermi surface, a wide variety of the superconducting gap structures can be realized in the odd parity superconductor, such as “hydrogen atom” of Weyl superconductor with novel crossed surface Andreev bound states.