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

Söde, Hajo; Talirz, Leopold; Gröning, Oliver; Pignedoli, Carlo Antonio; Berger, Reinhard; Feng, Xinliang; Müllen, Klaus; Fasel, Roman; Ruffieux, Pascal (2015). Electronic band dispersion of graphene nanoribbons via Fourier-transformed scanning tunneling spectroscopy. Physical review. B - condensed matter and materials physics, 91(4) American Physical Society 10.1103/PhysRevB.91.045429

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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±0.08me,0.40±0.18me, and 0.20±0.03me, 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±0.06 eV for 7-AGNRs adsorbed on Au(111).

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Departement of Chemistry and Biochemistry

UniBE Contributor:

Fasel, Roman

Subjects:

500 Science > 570 Life sciences; biology
500 Science > 540 Chemistry

ISSN:

1098-0121

Publisher:

American Physical Society

Language:

English

Submitter:

Roman Fasel

Date Deposited:

19 Mar 2015 11:31

Last Modified:

05 Feb 2016 12:12

Publisher DOI:

10.1103/PhysRevB.91.045429

BORIS DOI:

10.7892/boris.64991

URI:

https://boris.unibe.ch/id/eprint/64991

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