Berlin 2012 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 51: Topological Insulators II (jointly with MA, DS, O, TT)

HL 51.3: Vortrag

Mittwoch, 28. März 2012, 10:00–10:15, EB 301

Electronic properties and magnetic anisotropy of individual Co adatoms adsorbed on topological insulator surfaces — •T. Eelbo¹, M. Sikora², M. Waśniowska¹, M. Dobrzański², M. Gyamfi¹, G. Bihlmayer³, I. Miotkowski⁴, A. Kozlowski², and R. Wiesendanger¹ — ¹Institute of Applied Physics, University of Hamburg, Jungiusstr. 11, Hamburg, Germany — ²Department of Solid State Physics, AGH University of Science and Technology, Aleja Mickiewicza 30, Kraków, Poland — ³Peter Grünberg Institute and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, Jülich, Germany — ⁴Department of Physics, Purdue University, West Lafayette, USA

The interaction of magnetic impurities adsorbed on topological insulator surfaces causes changes of the electronic properties of the surfaces or the adatoms themselves. In addition the adatoms can present different magnetic properties due to interaction with the host. For this reason we studied the electronic properties and magnetic anisotropy of individual Co atoms adsorbed on Bi₂Se₃ by means of scanning tunneling microscopy/spectroscopy (STM/STS) and x-ray magnetic circular dichroism (XMCD) at low temperatures. After the deposition onto the cold surface STM measurements reveal two different adsorption sites for Co adatoms. Two resonances in the occupied states for both species of adatoms are found using STS. Moreover, XMCD measurements reveal a magnetic anisotropy with the easy axis being aligned out-of-plane. The experimental findings are compared to results of ab-initio calculations.