engleski

Electronic States of Epitaxial Graphene on Iridium from almost neutral to highly doped graphene

In this thesis we investigate graphene epitaxially grown on the (111) surface of iridium, primarily its electronic structure, possible interactions with the supporting substrate, and the impacts that enforced electron doping has on its bands. The thesis is organized as follows: In the first introductory chapter, we give an overview of the basic properties of graphene. Starting with the very definition of its structure, we continue by describing its electronic bands, the most notable consequences they leave to transport properties, and ways of producing graphene. In Chapter 2 the geometry of graphene grown on the (111) surface of iridium is described in both real and reciprocal space, special attention being given to the properties that will serve in describing the electron spectra in the following chapters. The main part of the thesis, that on electron spectroscopy of graphene on Ir(111), starts with spectroscopic characterization of the substrate in Chapter 3, which is a necessity since the features of the band structure of the substrate will appear in the spectra when graphene is added. Chapters 4 and 5 bring the main points of the thesis. Chapter 4 is on the electronic structure of graphene, and the changes its superstructural ordering has brought to it. Chapter 5 brings more complexity to the system, by electron doping of bands through alkali intercalation. A striking change of the bands is observed due to electron-phonon coupling, and a contribution to the general discussion on the strength of the coupling is given.

Photoemission; electronc structure; graphene

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