title: Three-dimensional Majorana fermions in chiral superconductors.
abstract: Using a systematic symmetry and topology analysis, we establish that three-dimensional chiral superconductors with strong spin-orbit coupling and odd-parity pairing generically host low-energy nodal quasiparticles that are spin-nondegenerate and realize Majorana fermions in three dimensions. By examining all types of chiral Cooper pairs with total angular momentumJformed by Bloch electrons with angular momentumjin crystals, we obtain a comprehensive classification of gapless Majorana quasiparticles in terms of energy-momentum relation and location on the Fermi surface. We show that the existence of bulk Majorana fermions in the vicinity of spin-selective point nodes is rooted in the nonunitary nature of chiral pairing in spin-orbit-coupled superconductors. We address experimental signatures of Majorana fermions and find that the nuclear magnetic resonance spin relaxation rate is significantly suppressed for nuclear spins polarized along the nodal direction as a consequence of the spin-selective Majorana nature of nodal quasiparticles. Furthermore, Majorana nodes in the bulk have nontrivial topology and imply the presence of Majorana bound states on the surface, which form arcs in momentum space. We conclude by proposing the heavy fermion superconductor PrOs4Sb12and related materials as promising candidates for nonunitary chiral superconductors hosting three-dimensional Majorana fermions.
authors.affiliation: Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Vladyslav
authors.initials: V
authors.lastname: Kozii
authors.affiliation: Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Jörn W F
authors.initials: JW
authors.lastname: Venderbos
authors.affiliation: Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Liang
authors.initials: L
authors.lastname: Fu
keywords: Majorana arcs; Majorana fermions; NMR spin relaxation; Spin-orbit coupling; heavy fermion skutterudites; topological nodal superconductors; unconventional superconductivity