  The possibility to engineer the coupling of spin and valley physics is
explored in ferroelectric oxide heterostructures with eg electronic
configuration. We show that the polar structural distortion induces the
appearance of spin-valley coupled properties, at the same time being
responsible for a topological transition from a quantum spin-Hall insulating
phase to a trivial band insulator. The coupled spin-valley physics is affected
by the topological band inversion in a non-trivial way; while the
valley-dependent spin polarization of both conduction and valence bands is
preserved, a change of the Berry curvature and of spin-valley selection rules
is predicted, leading to different circular dichroic response as well as valley
and spin Hall effects.
