# Topological Advantage for Adsorbate Chemisorption on Conjugated Chains

## TL;DR

This paper explores how topological properties of a polyacetylene chain affect chemisorption and electronic interactions with adsorbates.

## Contribution

The study reveals how topological phases influence adsorbate behavior through electronic phase transitions and localized midgap states.

## Key findings

- Localized midgap states at edges and solitons enhance electron donation compared to metallic and trivial phases.
- Electronic friction is highest in the metallic phase and suppressed in gapped regions.
- Topological boundaries show robustness to disorder and could be used in molecular catalysis and sensing.

## Abstract

Topological matter
offers opportunities for control of charge and
energy flow with implications for chemistry still incompletely understood.
In this work, we study an ensemble of adsorbates with an empty frontier
level (LUMO) coupled to the edges, domain walls (solitons), and bulk
of a Su–Schrieffer–Heeger polyacetylene chain across
its trivial insulator, metallic, and topological insulator phases.
We find that two experimentally relevant observables, charge donation
into the LUMO and the magnitude of adsorbate electronic friction,
are significantly impacted by the electronic phase of the SSH chain
and show clear signatures of the topological phase transition. Localized,
symmetry-protected midgap states at edges and solitons strongly enhance
electron donation relative to both the metallic and trivial phases,
whereas, by contrast, the metal’s extended states, despite
larger total DOS near the Fermi energy, hybridize more weakly with
a molecular adsorbate near a particular site. Electronic friction
is largest in the metal, strongly suppressed in gapped regions, and
intermediate at topological edges, where hybridization splits the
midgap resonance. These trends persist with disorder, highlighting
their robustness, and suggest engineering domain walls and topological
boundaries as pathways for employing topological matter in molecular
catalysis and sensing.