Dresden 2017 – scientific programme
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O: Fachverband Oberflächenphysik
O 94: Graphene: Electronic Properties, Structure and Substrate Interaction II
O 94.2: Talk
Thursday, March 23, 2017, 15:15–15:30, TRE Ma
Local electronic properties of the graphene-protected giant Rashba-split BiAg2 surface — •Julia Tesch1, Milan Jubitz1, Elena Voloshina2, Yuriy Dedkov1, and Mikhail Fonin1 — 1Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany — 2Institut für Chemie, Humboldt-Universität zu Berlin, 10099 Berlin, Germany
In search of future spintronic devices, combined systems of graphene and strongly Rashba-split surfaces, such as the heavy post-transition and noble metal surface alloy BiAg2, have become of particular interest.
Following a detailed discussion of the challenging yet well reproducible sample fabrication technique that allows us to fine tune the properties of the resulting system, we present a comprehensive study of the gr/BiAg2 structure by means of scanning tunnelling microscopy as well as spectroscopy supported by density functional theory calculations. Besides the persistent relativistic nature of graphene charge carriers upon adsorption, we report on a downward shift of the preserved BiAg2 surface state. This peculiar phenomenon can be explained by an inward relaxation of Bi atoms into the underlying thick Ag layer and thus a subsequent delocalisation of the surface state wavefunction. Despite the close proximity of the giant Rashba-split surface to graphene, no spin splitting has been observed in graphene in both experiment and theory, while the spin-texture of BiAg2 remains intact protected by graphene adsorption making this system a promising candidate for spintronic applications.