  Graphene was the first material predicted to be a time-reversal-invariant
topological insulator; however, the insulating gap is immeasurably small owing
to the weakness of spin-orbit interactions in graphene. A recent experiment [1]
demonstrated that designer honeycomb lattices with graphene-like "Dirac" band
structures can be engineered by depositing a regular array of carbon monoxide
atoms on a metallic substrate. Here, we argue that by growing such designer
lattices on metals or semiconductors with strong spin-orbit interactions, one
can realize an analog of graphene with strong intrinsic spin-orbit coupling,
and hence a highly controllable two-dimensional topological insulator. We
estimate the range of substrate parameters for which the topological phase is
achievable, and consider the experimental feasibility of some candidate
substrates.
