Dresden 2017 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 74: Graphene: Electronic Properties, Structure and Substrate Interaction II (joint session DY, DS, HL, MA, O, TT, organized by O)

TT 74.2: Vortrag

Donnerstag, 23. März 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.