Towards Realistic Amorphous Topological Insulators

The topological properties of materials are, until now, associated with the features of their crystalline structure, although translational symmetry is not an explicit requirement of the topological phases. Recent studies of hopping models on random lattices have demonstrated that amorphous materials can display a non-trivial topology. Using ab initio calculations we show that amorphous materials can also display topological insulator properties. More specifically, we present a realistic study of the electronic and transport properties of amorphous bismuthene systems, showing that they are topological insulators. These systems are characterized by the topological index Z₂=1 and bulk-edge duality, and their linear conductance is quantized, G=2e²/h, for Fermi energies within the topological gap. Our study opens the path to the investigation of amorphous topological insulator materials.