Topologically protected surface Majorana arcs and bulk Weyl fermions in ferromagnetic superconductors

A number of ferromagnetic superconductors have been recently discovered which are believed to be in the so-called equal spin pairing state. In the equal spin pairing state, the Cooper pairs condense forming order parameters Delta(up arrow up arrow), Delta(down arrow down arrow) which are decoupled in the spin sector. We show that these three-dimensional systems should generically support topologically protected surface Majorana arcs and bulk Weyl fermions as gapless excitations. Similar protected low-energy exotic quasiparticles should also appear in the recently discovered noncentrosymmetric superconductors in the presence of Zeeman splitting. The protected surface arcs can be probed by angle-resolved photoemission as well as Fourier transform scanning tunneling spectroscopy experiments.