We study the topological nature of single layers of correlated honeycomb materials $\alpha \text{−}{\mathrm{RuCl}}_3$ and $A_2{\mathrm{IrO}}_3$ $(A=\text{Li},\text{Na})$ with strong spin-orbit coupling. An effective tight-binding model based on first principles band structure calculations including Hubbard and spin-orbit coupling is derived. Two pairs of propagating edge modes centered at the zone center and zone boundary are found when their one-dimensional boundary forms a zigzag shape, while the bulk has a gap with trivial time-reversal $Z_2$ invariants. The effects of strong electronic interactions and doping on the edge modes in these Mott insulators are discussed. We further suggest a heterostructure of $\alpha \text{−}{\mathrm{RuCl}}_3/{\mathrm{IrCl}}_3$ to search for the proposed topological Mott phase.

• Received 16 May 2016
• Revised 20 July 2016

DOI:https://doi.org/10.1103/PhysRevB.94.121118