Electronic band dispersion of graphene nanoribbons via Fourier-transformed scanning tunneling spectroscopy

The electronic structure of atomically precise armchair graphene nanoribbons of width N = 7(7-AGNRs) are investigated by scanning tunneling spectroscopy (STS) on Au(111). We record the standing waves in the local density of states of finite ribbons as a function of sample bias and extract the disper...

Full description

Saved in:
Bibliographic Details
Published in:Physical review. B, Condensed matter and materials physics Condensed matter and materials physics, 2015-01, Vol.91 (4), Article 045429
Main Authors: Söde, Hajo, Talirz, Leopold, Gröning, Oliver, Pignedoli, Carlo Antonio, Berger, Reinhard, Feng, Xinliang, Müllen, Klaus, Fasel, Roman, Ruffieux, Pascal
Format: Article
Language:English
Subjects:
Condensed matter
Conduction band
Dispersions
Electronics
Graphene
Mathematical analysis
Nanostructure
Ribbons
Scanning tunneling microscopy
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The electronic structure of atomically precise armchair graphene nanoribbons of width N = 7(7-AGNRs) are investigated by scanning tunneling spectroscopy (STS) on Au(111). We record the standing waves in the local density of states of finite ribbons as a function of sample bias and extract the dispersion relation of frontier electronic states by Fourier transformation. The wave-vector-dependent contributions from these states agree with density functional theory calculations, thus enabling the unambiguous assignment of the states to the valence band, the conduction band, and the next empty band with effective masses of 0.41 + or - 0.08m sub(e), 0.40 + or - 0.18m sub(e), and 0.20 + or - 0.03m sub(e), respectively. By comparing the extracted dispersion relation for the conduction band to corresponding height-dependent tunneling spectra, we find that the conduction band edge can be resolved only at small tip-sample separations and has not been observed before. As a result, we report a band gap of 2.37 + or - 0.06 eV for 7-AGNRs adsorbed on Au(111).
ISSN:1098-0121
1550-235X
DOI:10.1103/PhysRevB.91.045429