  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.
