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.
@article{arxiv.1111.5058,
title = {Hexagonal pnictide SrPtAs: superconductivity with locally broken inversion symmetry},
author = {S. J. Youn and M. H. Fischer and S. H. Rhim and M. Sigrist and D. F. Agterberg},
journal= {arXiv preprint arXiv:1111.5058},
year = {2011}
}