Berlin 2015 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 13: Electronic Structure of Surfaces II

O 13.9: Vortrag

Montag, 16. März 2015, 17:15–17:30, MA 041

Rashba splitting of graphene-covered Au(111) revealed by quasiparticle interference mapping — •Mikhail Fonin, Philipp Leicht, Julia Tesch, Felix Blumenschein, Philipp Erler, and Luca Gragnaniello — Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany

Although the Rashba-split bands are readily visible in angle-resolved photoemission, their observation at the local scale employing quasiparticle interference (QPI) mappings is challenging. Here, we report on low-temperature scanning tunneling microscopy/spectroscopy measurements on epitaxial graphene flakes on Au(111). Careful analysis of the QPI maps allows the discrimination between the electronic systems of graphene and Au(111). Beyond the scattering vectors, which can be ascribed to the elastic scattering within each of the systems, we clearly observe QPI features related to the scattering process between graphene states and the Au(111) surface state. This additional interband scattering process at the graphene/Au(111) interface allows the direct quntitative determination of the magnitude of the Rashba splitting of the Au(111) surface state, which cannot be evaluated from QPI measurements on pure Au(111). This experiment demonstrates a new local spectroscopic approach to investigate the band structure of surfaces with Rashba splitting.