Tanmoy Das, A. V. Balatsky
Topological insulator represents 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 like magnetoelectric effect and topological Majorana excitations. Here we develop a theoretical formalism to show that three dimensional topological insulator can be designed artificially via staking 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 (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 $\Gamma$-momentum point. This approach offers an accessible way to design artificial topological insulators in a set up that takes full advantage of atomic layer deposition approach. This approach also allows us to bypass limitations imposed by bulk crystal geometry and is tunable.
View original:
http://arxiv.org/abs/1302.4514
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