Topological and trivial domain wall states in engineered atomic chains

TL;DR

This paper clarifies the distinction between trivial and topological domain wall states in engineered atomic chains, providing insights to better identify and manipulate topological states in atomic-scale systems.

Contribution

It explains why certain domain wall states are trivial and proposes methods to induce topological states, enhancing understanding of topological phenomena in atomic chains.

Findings

Identified trivial nature of certain domain wall states

Proposed methods to realize topological domain wall states

Enhanced understanding of topological vs trivial states

Abstract

In a recent article, Huda et al. demonstrated tuneable topological domain wall states in the c(2$\times$2) chlorinated Cu(100). Their system allows to experimentally tune the domain wall states using atom manipulation by the tip of a scanning tunneling microscope (STM). They have realized topological domain wall states of two prototypical 1D models such as trimer and coupled dimer chains. However, they did not distinguish trivial domain wall states from topological ones in their models. As a result, all states of a specific domain wall are not topological but trivial. Here, we show why the specific domain wall states are trivial and how to make them topological. This topological consideration would provide more clear insight on future studies on topological domain wall states in artificial atomic chains.