  In the quest for topological insulators with large band gaps,
heterostructures with Rashba spin-orbit interactions come into play. Transition
metal oxides with heavy ions are especially interesting in this respect. We
discuss the design principles for stacking oxide Rashba layers. Assuming a
single layer with a two-dimensional electron gas (2DEG) on both interfaces as a
building block, a two-dimensional topological insulating phase is present when
negative coupling between the 2DEGs exists. When stacking multiple building
blocks, a two-dimensional or three-dimensional topological insulator is
artificially created, depending on the intra- and interlayer coupling strengths
and the number of building blocks. We show that the three-dimensional
topological insulator is protected by reflection symmetry, and can therefore be
classified as a topological crystalline insulator. In order to isolate the
topological states from bulk states, the intralayer coupling term needs to be
quadratic in momentum. It is described how such a quadratic coupling could
potentially be realized by taking buckling within the layers into account. The
buckling, thereby, brings the idea of stacked Rashba system very close to the
alternative approach of realizing the buckled honeycomb lattice in
[111]-oriented perovskite oxides.
