Structural and electronic properties of realistic two-dimensional amorphous topological insulators

TL;DR

This study demonstrates that two-dimensional amorphous bismuthene structures can retain topological insulator properties, with robustness influenced by spin-orbit coupling and gap size, and confirms their electronic transport characteristics.

Contribution

It provides a realistic modeling approach for amorphous topological insulators and explores their topological and transport properties throughout amorphization.

Findings

Topological insulator phase persists in amorphous bismuthene.

Conductance plateau at 2e^2/h within the topological gap.

Localization effects emerge in trivial insulator phase.

Abstract

We investigate the structure and electronic spectra properties of two-dimensional amorphous bismuthene structures and show that these systems are topological insulators. We employ realistic modeling of amorphous geometries together with density functional theory for electronic structure calculations. We investigate the system topological properties throughout the amorphization process and find that the robustness of the topological phase is associated with the spin-orbit coupling strength and size of the pristine topological gap. Using recursive non-equilibrium Green's function, we study the electronic transport properties of nanoribbons devices with lengths comparable to experimentally synthesized materials. We find a $2e^2/h$ conductance plateau within the topological gap and an onset of Anderson localization at the trivial insulator phase.