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TT: Fachverband Tiefe Temperaturen

TT 78: Graphene: Electronic Properties (organized by O)

TT 78.12: Vortrag

Mittwoch, 2. April 2014, 18:45–19:00, WIL C107

Highly spin-polarized Dirac fermions at the graphene-Co interface — •Dmitry Marchenko^1,2, Andrei Varykhalov¹, Jaime Sánchez- Barriga¹, and Oliver Rader¹ — ¹Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany — ²Physikalische und Theoretische Chemie, Freie Universität Berlin, Berlin, Germany

The interface of graphene with ferromagnets is very interesting for spintronics due to possible use of peculiar graphene electronic structure in transport and spin-filter applications when graphene is used together with nickel or cobalt as ferromagnetic contacts for spin injection and detection [1]. Despite a strong hybridization between graphene and ferromagnetic substrate states the graphene Dirac cone was observed by angle-resolved photoemission without gap between pi and pi* parts [2]. Here we report strong spin polarization of the Dirac cone measured by spin- and angle-resolved photoemission. Wave-vector dependent measurements exclude a Rashba-type spin-orbit contribution to the spin polarization; ferromagnetic origin is verified by reversal of the remanent magnetization. The importance of the spin polarization at the interface for spin filtering is pointed out.

[1] V. M. Karpan et al., Phys. Rev. Lett. 99, 176602 (2007) [2] A. Varykhalov et al., Phys. Rev. X 2, 041017 (2012)