Hexagonal pnictide SrPtAs: superconductivity with locally broken   inversion symmetry
  Unlike other pnictides, SrPtAs has a hexagonal structure, containing layers with As-Pt atoms that form a honeycomb lattice. These layers lack inversion symmetry which allows for a spin-orbit coupling that we show has a dramatic effect on superconductivity in this material. In particular, for conventional s-wave superconductivity in SrPtAs, both the spin susceptibility and the paramagnetic limiting field are enhanced significantly with respect to that usually expected for s-wave superconductors. SrPtAs provides a prime example of a superconductor with locally broken inversion symmetry. 
S. J. Youn, M. H. Fischer, S. H. Rhim, M. Sigrist, and D. F. Agterberg
cond-mat.supr-con cond-mat.str-el