Anisotropy of quasiparticle lifetimes and the role of disorder in graphite from ultrafast time-resolved photoemission spectroscopy

Femtosecond time-resolved photoemission of photoexcited electrons in highly oriented pyrolytic graphite (HOPG) provides strong evidence for anisotropies of quasiparticle (QP) lifetimes. Indicative of such anisotropies is a pronounced anomaly in the energy dependence of QP lifetimes between 1.1 and 1...

Full description

Saved in:
Bibliographic Details
Published inPhysical review letters Vol. 87; no. 26; p. 267402
Main Authors Moos, G, Gahl, C, Fasel, R, Wolf, M, Hertel, T
Format Journal Article
LanguageEnglish
Published United States 24.12.2001
Online AccessGet more information

Cover

More Information
Summary:Femtosecond time-resolved photoemission of photoexcited electrons in highly oriented pyrolytic graphite (HOPG) provides strong evidence for anisotropies of quasiparticle (QP) lifetimes. Indicative of such anisotropies is a pronounced anomaly in the energy dependence of QP lifetimes between 1.1 and 1.5 eV--the vicinity of a saddle point in the graphite band structure. This is supported by recent ab initio calculations and a comparison with experiments on defect-enriched HOPG which reveal that disorder, e.g., defects or phonons, increases electron energy relaxation rates.
ISSN:0031-9007
DOI:10.1103/physrevlett.87.267402