Five-Membered Rings Create Off-Zero Modes in Nanographene

The low-energy electronic structure of nanographenes can be tuned through zero-energy π-electron states, typically referred to as zero-modes. Customizable electronic and magnetic structures have been engineered by coupling zero-modes through exchange and hybridization interactions. Manipulation of the energy of such states, however, has not yet received significant attention. We find that attaching a five-membered ring to a zigzag edge hosting a zero-mode perturbs the energy of that mode and turns it into an off-zero mode: a localized state with a distinctive electron-accepting character. Whereas the end states of typical 7-atom-wide armchair graphene nanoribbons (7-AGNRs) lose their electrons when physisorbed on Au(111) (due to its high work function), converting them into off-zero modes by introducing cyclopentadienyl five-membered rings allows them to retain their single-electron occupation. This approach enables the magnetic properties of 7-AGNR end states to be explored using scanning tunneling microscopy (STM) on a gold substrate. We find a gradual decrease of the magnetic coupling between off-zero mode end states as a function of GNR length, and evolution from a more closed-shell to a more open-shell ground state.

Medienart:

E-Artikel

Erscheinungsjahr:

2023

Erschienen:

2023

Enthalten in:

Zur Gesamtaufnahme - volume:17

Enthalten in:

ACS nano - 17(2023), 24 vom: 26. Dez., Seite 24901-24909

Sprache:

Englisch

Beteiligte Personen:

Jacobse, Peter H [VerfasserIn]
Daugherty, Michael C [VerfasserIn]
Čerņevičs, Kristia Ns [VerfasserIn]
Wang, Ziyi [VerfasserIn]
McCurdy, Ryan D [VerfasserIn]
Yazyev, Oleg V [VerfasserIn]
Fischer, Felix R [VerfasserIn]
Crommie, Michael F [VerfasserIn]

Links:

Volltext

Themen:

Electronic structure
Five-membered rings
Journal Article
Magnetic ground state
Nanographenes
Open shell
Scanning tunneling microscopy
Zero-modes

Anmerkungen:

Date Revised 31.01.2024

published: Print-Electronic

Citation Status PubMed-not-MEDLINE

doi:

10.1021/acsnano.3c06006

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM365427071