Dual nature of localized phase defects in the In/Si(111) atomic wire array: impurities and short topological solitons

TL;DR

This paper uncovers two types of localized phase defects in indium atomic wires on Si(111), distinguishing between impurity-induced defects and genuine topological solitons using microscopy and computational methods.

Contribution

It identifies and characterizes atomically-sized topological solitons in a quasi-1D charge density wave system, differentiating them from impurity-related defects.

Findings

Identification of two types of phase flip structures: impurity-induced and topological solitons.

Demonstration that topological solitons are abrupt left-chiral structures.

Use of combined microscopy and density-functional calculations to analyze defect nature.

Abstract

We demonstrate the existence of atomically-sized topological solitons in a quasi one-dimensional charge density wave system: indium atomic wires on Si(111). Performing joint scanning tunneling microscopy and density-functional calculations, we show that the Si(111)-(8x2)In surface features two conceptually different types of abrupt phase flip structures. One is caused by In adatoms and is, hence, non-solitonic in nature. The other one is an abrupt left-chiral soliton.