Berlin 2015 – scientific programme
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O: Fachverband Oberflächenphysik
O 48: Graphene: Dynamics
O 48.4: Talk
Wednesday, March 18, 2015, 11:15–11:30, MA 041
Anisotropic Intravalley Scattering in Strongly Doped Graphene — •Daniela Dombrowski1, Wouter Jolie1, Sven Runte1, Marin Petrović2, Fabian Craes1, Jürgen Klinkhammer1, Marko Kralj2, Predrag Lazić3, Eran Sela4, and Carsten Busse1 — 1II. Physikalisches Institut, Universität zu Köln, Germany — 2Institut za fiziku, Croatia — 3Institut Ruđer Bošković, Croatia — 4Raymond and Beverly Sackler School of Physics and Astronomy, Tel-Aviv University, Israel
We perform Fourier-transform scanning tunneling spectroscopy (FT-STS) studies on Cs intercalated graphene on Ir(111). Angle-resolved photoemission spectroscopy (ARPES) measurements show, that the Cs strongly n-dopes graphene and shifts the Fermi level into the region of strong trigonal warping. We observe intervalley scattering and additionally a clear feature of intravalley scattering, which exhibits an anisotropic intensity distribution with dominant scattering in Γ-M direction.
In the linear region of the Dirac cone, conservation of pseudospin leads to the suppression of intravalley scattering since the direction of the pseudospin is either parallel or antiparallel to the momentum, thus the system has well defined chirality. This is no longer valid in the trigonal warping region near the Van-Hove singularity.
The FT-STS results are supplemented by density functional calculations of the electronic band structure and simulations of the scattering pattern based on the T-matrix theory.