Tunable ferromagnetic Weyl fermions from a hybrid nodal ring

Realization of nontrivial band topology in condensed matter systems is of great interest in recent years.Using first-principles calculations and symmetry analysis,we propose an exotic topological phase with tunable ferromagnetic Weyl fermions in a halfmetallic oxide CrP_(2)O_(7).In the absence of spin–orbit coupling(SOC),we reveal that CrP_(2)O_(7) possesses a hybrid nodal ring.When SOC is present,the spin-rotation symmetry is broken.As a result,the hybrid nodal ring shrinks to discrete nodal points and forms different types of Weyl points.The Fermi arcs projected on the(100)surface are clearly visible,which can contribute to the experimental study for the topological properties of CrP_(2)O_(7).In addition,the calculated quasiparticle interference patterns are also highly desirable for the experimental study of CrP_(2)O_(7).Our findings provide a good candidate of ferromagnetic Weyl semimetals,and are expected to realize related topological applications with their attracted features.