Please use this identifier to cite or link to this item: https://doi.org/10.1103/PhysRevB.84.081403
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dc.titleObservation of room-temperature high-energy resonant excitonic effects in graphene
dc.contributor.authorSantoso, I.
dc.contributor.authorGogoi, P.K.
dc.contributor.authorSu, H.B.
dc.contributor.authorHuang, H.
dc.contributor.authorLu, Y.
dc.contributor.authorQi, D.
dc.contributor.authorChen, W.
dc.contributor.authorMajidi, M.A.
dc.contributor.authorFeng, Y.P.
dc.contributor.authorWee, A.T.S.
dc.contributor.authorLoh, K.P.
dc.contributor.authorVenkatesan, T.
dc.contributor.authorSaichu, R.P.
dc.contributor.authorGoos, A.
dc.contributor.authorKotlov, A.
dc.contributor.authorRübhausen, M.
dc.contributor.authorRusydi, A.
dc.date.accessioned2014-10-07T04:33:37Z
dc.date.available2014-10-07T04:33:37Z
dc.date.issued2011-08-10
dc.identifier.citationSantoso, I., Gogoi, P.K., Su, H.B., Huang, H., Lu, Y., Qi, D., Chen, W., Majidi, M.A., Feng, Y.P., Wee, A.T.S., Loh, K.P., Venkatesan, T., Saichu, R.P., Goos, A., Kotlov, A., Rübhausen, M., Rusydi, A. (2011-08-10). Observation of room-temperature high-energy resonant excitonic effects in graphene. Physical Review B - Condensed Matter and Materials Physics 84 (8) : -. ScholarBank@NUS Repository. https://doi.org/10.1103/PhysRevB.84.081403
dc.identifier.issn10980121
dc.identifier.urihttp://scholarbank.nus.edu.sg/handle/10635/82797
dc.description.abstractUsing a combination of ultraviolet-vacuum ultraviolet reflectivity and spectroscopic ellipsometry, we observe a resonant exciton at an unusually high energy of 6.3 eV in epitaxial graphene. Surprisingly, the resonant exciton occurs at room temperature and for a very large number of graphene layers N≈75, thus suggesting a poor screening in graphene. The optical conductivity (σ1) of a resonant exciton scales linearly with the number of graphene layers (up to at least 8 layers), implying the quantum character of electrons in graphene. Furthermore, a prominent excitation at 5.4 eV, which is a mixture of interband transitions from π to π* at the M point and a π plasmonic excitation, is observed. In contrast, for graphite the resonant exciton is not observable but strong interband transitions are seen instead. Supported by theoretical calculations, for N≤ 28 the σ1 is dominated by the resonant exciton, while for N> 28 it is a mixture between exitonic and interband transitions. The latter is characteristic for graphite, indicating a crossover in the electronic structure. Our study shows that important elementary excitations in graphene occur at high binding energies and elucidate the differences in the way electrons interact in graphene and graphite. © 2011 American Physical Society.
dc.description.urihttp://libproxy1.nus.edu.sg/login?url=http://dx.doi.org/10.1103/PhysRevB.84.081403
dc.sourceScopus
dc.typeArticle
dc.contributor.departmentPHYSICS
dc.contributor.departmentCHEMISTRY
dc.contributor.departmentELECTRICAL & COMPUTER ENGINEERING
dc.description.doi10.1103/PhysRevB.84.081403
dc.description.sourcetitlePhysical Review B - Condensed Matter and Materials Physics
dc.description.volume84
dc.description.issue8
dc.description.page-
dc.description.codenPRBMD
dc.identifier.isiut000293774600002
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