  A general approach is derived for constructing an effective spin-orbit
Hamiltonian for nonmagnetic materials, which is useful for calculating
spin-dependent properties near an arbitrary point in momentum space with
pseudospin degeneracy. The formalism is verified through comparisons with other
approaches for III-V semiconductors, and its general applicability is
illustrated by deriving the spin-orbit interaction and predicting spin
lifetimes for strained SrTiO$_3$ and a two-dimensional electron gas in
SrTiO$_3$ (such as at the LaAlO$_3$/SrTiO$_3$ interface). These results suggest
robust spin coherence and spin transport properties in SrTiO$_3$-based
materials at room temperature.
