  The effect of spin-orbit coupling on the electronic structure of the layered
iron-free pnictide superconductor, SrPtAs, has been studied using the full
potential linearized augmented plane wave method. The anisotropy in Fermi
velocity, conductivity and plasma frequency stemming from the layered structure
are found to be enhanced by spin-orbit coupling. The relationship between
spin-orbit interaction and the lack of two-dimensional inversion in the PtAs
layers is analyzed within a tight-binding Hamiltonian based on the
first-principles calculations. Finally, the band structure suggests that
electron doping could increase $T_c$.
