Na4Ir3O8 as a 3D spin liquid with fermionic spinons
  Spin liquid states for spin-1/2 antiferromagnetic Heisenberg model on a hyperkagome lattice are studied. We classify and study flux states according to symmetries. Applying this model to Na4Ir3O8, we propose that the high temperature state may be described by a spinon Fermi surface, which forms a paired state with line nodes below 20 K. The possible mixed spin singlet and spin triplet pairing states are discussed according to the lattice symmetry which breaks inversion. 
Yi Zhou, Patrick A. Lee, Tai-Kai Ng, and Fu-Chun Zhang