# Dresden 2014 – wissenschaftliches Programm

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# HL: Fachverband Halbleiterphysik

## HL 105: Poster: Topological insulators (with MA/O)

### HL 105.12: Poster

### Donnerstag, 3. April 2014, 17:00–20:00, P1

**Combined XMCD and STS study of transition metal adatoms adsorbed on the surface of prototypical 3D topological insulators** — •Jonas Warmuth^{1}, Martin Vondráček^{2}, Matteo Michiardi^{3}, Lucas Barreto^{3}, Cinthia Piamonteze^{4}, Andreas Eich^{1}, Alexander Khajetoorians^{1}, Jan Honolka^{2}, Jian-Li Mi^{3}, Bo Brummerstedt Iversen^{3}, Philip Hofmann^{3}, Jens Wiebe^{1}, and Roland Wiesendanger^{1} — ^{1}Institute of Applied Physics, Uni Hamburg, Germany — ^{2}Institute of Physics ASCR, Prague, Czech Republic — ^{3}iNano, Aarhus University, Denmark — ^{4}Laboratory of Condensed Matter Physics, PSI, Switzerland

The spin of Dirac electrons in topological surface states is rigidly locked to the direction of their momentum leading, e.g., to prohibited backscattering. Their interaction with magnetic impurities is currently a matter of debate, because it can destroy this effect, heavily depending on the magnetic properties of the impurities. Using x-ray magnetic circular dichroism techniques we investigated 3d transition metal adatoms adsorbed on the surface of different prototypical 3D topological insulators. We compare our results to crystal field multiplet calculations [1] of the 3d states. For some of the adatom species, we find a considerable magnetic anisotropy, which depends crucially on the coupling of their 3d states to the substrate electrons. Furthermore, we investigate the interaction of the adatoms and the Dirac electrons by Fourier-transform scanning tunneling spectroscopy [2], which reveals shifts of the linear dispersion due to surface doping effects.

J. Honolka et al., PRL 108, 256811 (2012)