Anisotropic dispersion and partial localization of acoustic surface plasmons on an atomically stepped surface: Au(788).
Understanding acoustic surface plasmons (ASPs) in the presence of nanosized gratings is necessary for the development of future devices that couple light with ASPs. We show here by experiment and theory that two ASPs exist on Au(788), a vicinal surface with an ordered array of monoatomic steps. The ASPs propagate across the steps as long as their wavelength exceeds the terrace width, thereafter becoming localized. Our investigation identifies, for the first time, ASPs coupled with intersubband transitions involving multiple surface-state subbands.
IMEM-CNR Unitá Operativa di Genova, Via Dodecaneso 33, 16146 Genova, Italy.
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Smerieri
IMEM-CNR Unitá Operativa di Genova, Via Dodecaneso 33, 16146 Genova, Italy and Dipartimento di Fisica dell'Universitá di Genova, Via Dodecaneso 33, 16146 Genova, Italy.
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Vattuone
IMEM-CNR Unitá Operativa di Genova, Via Dodecaneso 33, 16146 Genova, Italy.
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Savio
Institut für Festkörperphysik, Abteilung Atomare und Molekulare Strukturen, Leibniz Universität Hannover, Appelstrasse 2, D-30167 Hannover, Germany.
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Langer
Institut für Festkörperphysik, Abteilung Atomare und Molekulare Strukturen, Leibniz Universität Hannover, Appelstrasse 2, D-30167 Hannover, Germany.
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Tegenkamp
Institut für Festkörperphysik, Abteilung Atomare und Molekulare Strukturen, Leibniz Universität Hannover, Appelstrasse 2, D-30167 Hannover, Germany.
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Pfnür
Departamento de Física de Materiales, Facultad de Ciencias Químicas, Universidad del País Vasco, Apartado 1072, 20080 San Sebastián/Donostia, Spain and Donostia International Physics Center (DIPC), Paseo de Manuel Lardizabal 4, 20018 San Sebastián/Donostia, Spain and IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain.
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Silkin
IMEM-CNR Unitá Operativa di Genova, Via Dodecaneso 33, 16146 Genova, Italy and Dipartimento di Fisica dell'Universitá di Genova, Via Dodecaneso 33, 16146 Genova, Italy.
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Rocca