Berlin 2015 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 67: Topological insulators I (MA with HL/TT)
HL 67.7: Talk
Thursday, March 19, 2015, 11:00–11:15, EB 202
The magnetism of Ni adatoms adsorbed on the TI Bi2Te2Se — Jan Honolka1, Martin Vondráček1, •Lasse Cornils2, Malte Schüler3, Markus Dunst4, Jonas Warmuth2, Lihui Zhou2, Anand Kamlapure2, Alexander Ako Khajetoorians2,5, Matteo Michiardi6, Lucas Barreto6, Philip Hofmann6, Jian-Li Mi6, Martin Bremholm6, Bo B. Iversen6, Cinthia Piamonteze7, Hubert Ebert4, Jan Minar4,8, Tim Wehling3, Roland Wiesendanger2, and Jens Wiebe2 — 1Inst. of Physics ASCR, Prague, Czech Republic — 2INF, University of Hamburg, Germany — 3Inst. of Theo. Physics, University of Bremen, Germany — 4LMU München, Germany — 5IMM, Radboud University Nijmegen, The Netherlands — 6iNano, Aarhus University, Denmark — 7PSI, Switzerland — 8New Technologies-Research Center, University of West Bohemia, Pilsen, Czech Republic
The predicted gap opening in the surface state of topological insulators (TIs) induced by surface magnetic doping, and the associated novel electron phases, have recently caught strong interest of the scientific community. However, the experimental evidence of an induced gap opening is still controversial [1] and calls for a detailed investigation of the magnetism of different adatoms. Here, we show by a combined XMCD, ARPES and STS study, that Ni adatoms on the TI Bi2Te2Se reveal a surprising behaviour: While there is no detectable XMCD signal at the Ni L2,3-edges, the XAS spectrum unveils a considerable resonant absorption of the d-shell. The results are analyzed by ab-initio calculations. [1] J. Honolka et al., PRL 108, 256811 (2012).