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TT: Fachverband Tiefe Temperaturen
TT 97: Graphene: Structure (jointly with O, HL)
TT 97.1: Vortrag
Donnerstag, 19. März 2015, 10:30–10:45, MA 041
Manganese Intercalation in Graphene/Ir(111): a structural study — •Stefan Böttcher1, Hendrik Vita1, Yuriy S. Dedkov2, and Karsten Horn1 — 1Fritz-Haber Institute, Faradayweg 4-6, 14195 Berlin — 2SPECS Surface Nano Analysis GmbH, Voltastrasse 5, 13355 Berlin
The graphene/substrate interaction is of interest for a many applications, and to understand and classify the interaction mechanism as such. For example, the 3d transition metals Fe, Co and Ni on the one hand, and Cu on the other suggest that a classification into strongly and weakly interacting systems may be possible, as judged by criteria such as the survival of the Dirac cone or the crystallographic structure of the graphene layer. Here we present a structural study, through LEED and STM, of manganese intercalation on graphene/Ir(111), a system that has so far not been studied. We follow the stages of the intercalation process, from the deposition of Mn on top through the formation of the intercalated phase. Manganese is found to be arranged pseudomorphically to the Ir(111) substrate underneath graphene. While several criteria for a weak interaction are fulfilled, the graphene/Mn/Ir(111) system also shows structural evidence for a strong interaction between the graphene and the Mn layer, e.g. a lower separation between graphene and the intercalated layer, a conclusion that is further supported by ARPES. Manganese intercalation may therefore be special because it fills the gap between the strongly and weakly interacting transition metals. In addition, at higher intercalation temperatures a new, possibly surface alloyed phase is observed.