Effect of electron-phonon interaction on the formation of one-dimensional electronic states in coupled Cl vacancies

TL;DR

This study investigates how strong electron-phonon interactions influence the formation of extended electronic states in one-dimensional vacancy chains in NaCl on Cu(111), revealing phonon effects on energy splitting and band structure emergence.

Contribution

It provides experimental and theoretical insights into how electron-phonon coupling affects electronic state formation in atomic-scale vacancy chains.

Findings

Electron-phonon interaction enlarges energy splitting via level repulsion.

Vacancy chains exhibit emerging band structures.

Phonon dressing influences electronic state broadening.

Abstract

The formation of extended electron states in one-dimensional nanostructures is of key importance for the function of molecular electronics devices. Here we study the effects of strong electron-phonon interaction on the formation of extended electronic states in intentionally created Cl vacancy pairs and chains in a NaCl bilayer on Cu(111). The interaction between the vacancies was tailored by fabricating vacancy pairs and chains of different orientation and separation with atomic precision using vertical manipulation. Small separation of divacancies led to the formation of symmetric and antisymmetric vacancy states and localized interface-states. By scanning tunneling spectroscopy (STS) we measured their energy splitting and broadening as a function of the inter-vacancy separation. Unexpectedly, the energy splitting between the vacancy states is enlarged by level repulsion resulting from phonon dressing of the electronic states, as evidenced by theory. Already for a few coupled vacancies we observe an emerging band structure of the defect band.