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

Abstract

A number of ferromagnetic superconductors have been recently discovered which are believed to be in the so-called "equal spin pairing" (ESP) state. In the ESP state the Cooper pairs condense forming order parameters $Δ_{\uparrow\uparrow}, Δ_{\downarrow\downarrow}$ 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 non-centrosymmteric superconductors in the presence of a Zeeman field. The protected surface arcs can be probed by angle-resolved photoemission (ARPES) as well as scanning tunneling microscope (STM) experiments.

5 pages and 2 figures; Figure 2 revised, typos corrected