ELS-LEED study of low-dimensional plasmons in DySi_1tn2 layers and nanowires [Elektronische Ressource] / von Eddy Patrick Rugeramigabo

ELS-LEED study of low-dimensionalplasmons in DySi layers and2nanowiresVon der Fakultat¨ fur¨ Mathematik und Physikder Gottfried Wilhelm Leibniz Universitat¨ Hannoverzur Erlangung des GradesDoktor der NaturwissenschaftenDr. rer. nat.genehmigte DissertationvonDipl.-Phys. Eddy Patrick Rugeramigabogeboren am 17. Marz¨ 1975in Bujumbura (Burundi)2007Referent: Prof. Dr. H. Pfnur¨Korreferent: Prof. Dr. M. RoccaTag der Promotion: 30.11.2007iiAbstractLow-dimensional dysprosium silicide metal systems grown on Si have been character-ized by means of energy loss spectroscopy of low energy electron diffraction. The sev-eral silicide phases depending on the growth conditions have been observed. Moreovercollective charge excitations were clearly detected and identified as low-dimensionalplasmons which have a different dispersion compared to the well known bulk and sur-face plasmons.Dy-silicide has been grown on Si(111) by means of molecular beam epitaxy. Due to itssmall lattice mismatch (-0.3%) to Si(111), Dy-silicide grows in epitaxial high qualitycrystalline layers. In the submonolayer regime, many silicide phases coexist until thesilicide coverage approaches 1ML, and shows the characteristic 11 diffraction pat-tern with the stoichiometry DySi . With further increasing of the coverage, the silicide2turns to the multilayer phase. The collective electronic excitations in the monolayerstructure have been found to have a 2D-character.