Berlin 2015 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 85: Topological Insulators 2 (MA with HL/TT)
HL 85.7: Talk
Thursday, March 19, 2015, 16:30–16:45, EB 202
first principle study of structural, electronic and magnetic properties of graphene nanoribbons deposited on the topological insulator Sb2Te3 — wei zhang1,2, •farideh hajiheidari1, yan li1,3, manuel j. schmidt1, and riccardo mazzarello1,4 — 1Institute for Theoretical Solid State Physics, RWTH Aachen University, D-52074 Aachen, Germany — 2Institute of Physics (IA), RWTH Aachen University, 52056 Aachen, Germany — 3IEK-6, Forschungszentrum Jülich, D-52425 Jülich, Germany — 4JARA-FIT and JARA-HPC, RWTH Aachen University, D-52074 Aachen, Germany
Magnetic perturbations are known to affect the surface properties of a topological insulator (TI) dramatically. According to mean-field calculations, zigzag graphene nanoribbons (zGNRs) possess spin-polarized edge states. Hence, zGNRs deposited on a TI could be a promising candidate for an experimental investigation of proximity effects between a magnetic system and a TI. In this work, we carry out a first-principles investigation based on density functional theory of zGNRs on the Sb2Te3 (001) surface. We use gradient-corrected density functionals in combination with semi-empirical van der Waals corrections. Both H-free and H-terminated zGNRs are considered. In the case of H-free zGNRs, the strong interaction between the edge atoms and the TI surface is shown to lead to the bending of the zGNRs , however, the edge magnetism is preserved. Moreover, the magnetic anisotropy axis is perpendicular to the surface of the substrate. In the H-terminated case, on the other hand, the interaction is less significant and edge magnetism is fully preserved.