Dresden 2017 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 46: Electronic Structure of Surfaces: Spectroscopy, Surface States
O 46.13: Poster
Dienstag, 21. März 2017, 18:30–20:30, P1A
Quasiparticle interferences in highly doped bilayer graphene — •Wouter Jolie1, Jonathan Lux2, Mathias Pörtner1, Tobias Hartl1, Timo Knispel1, Sabina Simon1,3, Charlotte Herbig1, Thomas Michely1, and Carsten Busse1,4 — 1II. Physikalisches Institut, Universität zu Köln — 2Institut für Theoretische Physik, Universität zu Köln — 3Fachbereich Physik, Universität Konstanz — 4Institut für Materialphysik, Universität Münster
When two graphene layers are Bernal stacked as in graphite, the two low-energy bands can be described by massive Dirac fermions and it has been demonstrated that doping such a graphene bilayer not only shifts its chemical potential, but also opens up a band gap [1]. We dope bilayer graphene to populate the second conduction band and measure quasiparticle interferences (QPI) with scanning tunneling microscopy and spectroscopy.
We grow bilayer graphene on Ir(111) with a combination of chemical vapor deposition (creating a monolayer of high perfection) and physical vapor deposition (forming a second graphene layer at the interface). Subsequently, Cs is intercalated between the bilayer and the metal underneath.
We observe complex standing waves patterns at various energies and obtain the scattering vectors responsible for QPI using a Fourier transform analysis. We compare our results with simulations based on the T-matrix theory as well as tight-binding calculations and explore the origin of the suppression of certain scattering processes.
[1] E. V. Castro et al., Phys. Rev. Lett. 99, 216802 (2007)