Stabilizing topological phases in graphene via random adsorption

TL;DR

This paper investigates how random adsorption of atoms on graphene can induce topological phases by weakening intervalley scattering, thus transforming trivial insulators into topological states.

Contribution

It demonstrates that random adatom distribution enhances the realization of topological phases in graphene by suppressing intervalley scattering, a novel approach compared to periodic arrangements.

Findings

Random adatom distribution weakens intervalley scattering.

Randomization converts trivial insulators into topological states.

Spin-orbit coupling remains unaffected by adatom randomness.

Abstract

We study the possibility of realizing topological phases in graphene with randomly distributed adsorbates. When graphene is subjected to periodically distributed adatoms, the enhanced spin-orbit couplings can result in various topological phases. However, at certain adatom coverages, the intervalley scattering renders the system a trivial insulator. By employing a finite-size scaling approach and Landauer-B\"{u}ttiker formula, we show that the randomization of adatom distribution greatly weakens the intervalley scattering, but plays a negligible role in spin-orbit couplings. Consequently, such a randomization turns graphene from a trivial insulator into a topological state.