  Topological insulators represent a new class of quantum phase defined by
invariant symmetries and spin-orbit coupling that guarantees metallic Dirac
excitations at its surface. The discoveries of these states have sparked the
hope of realizing nontrivial excitations and novel effects such as a
magnetoelectric effect and topological Majorana excitations. Here we develop a
theoretical formalism to show that a three dimensional topological insulator
can be designed artificially via stacking bilayers of two-dimensional Fermi
gases with opposite Rashba-type spin-orbit coupling on adjacent layers, and
with inter-layer quantum tunneling. We demonstrate that in the stack of
bilayers grown along a (001)-direction, a nontrivial topological phase
transition occurs above a critical number of Rashba-bilayers. In the
topological phase we find the formation of a single spin-polarized Dirac cone
at the $\Gamma$-point. This approach offers an accessible way to design
artificial topological insulators in a set up that takes full advantage of the
atomic layer deposition approach. This design principle is tunable and also
allows us to bypass limitations imposed by bulk crystal geometry.

Mesoscale and Nanoscale Physics;Materials Science