Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 103: Transport: Poster Session

TT 103.41: Poster

Thursday, March 19, 2015, 15:00–18:00, Poster B

XMCD of 3d adatoms on Bi₂Te₃ and Bi₂Te₂Se: experiment and ab-initio theory — Martin Vondraček¹, Malte Schüler⁵, Markus Dunst⁷, Cinthia Piamonteze², Jonas Warmuth⁴, Matteo Michiardi³, Lucas Barreto³, Alexander Ako Khajetoorians^4,6, Jian-Li Mi³, Bo B. Iversen³, Philip Hofmann³, Jens Wiebe⁴, Tim Wehling⁵, Jan Minár^7,8, Hubert Ebert⁷, Roland Wiesendanger⁴, and •Jan Honolka¹ — ¹Inst. of Physics ASCR, Prague, CZ — ²PSI, CH — ³iNano, Aarhus Univ., DK — ⁴INF, Univ. of Hamburg, DE — ⁵Inst. of Theo. Physics, Univ. of Bremen, DE — ⁶Radboud Univ. Nijmegen, Inst. for Molec. and Mat., NL — ⁷LMU München, DE — ⁸Univ. of West Bohemia, CZ

The chalcogenide 3D topological insulator Bi₂Te₃ obeys time-reversal symmetry and hosts a linear dispersive, topological surface state around the Gamma point. It is predicted that magnetic adatoms can break time-reversal symmetry, thereby generating an energy gap at the Dirac point of the otherwise topologically protected surface states [1].

Here we summarize experimental XAS and XMCD results of single 3d adatoms Ni, Fe, and Cu on Bi₂Te₃ and Bi₂Te₂Se surfaces. While Cu shows a d¹⁰ electronic configuration, we find a significant resonant Ni L_2,3 intensity in XAS, however no magnetic dichroism within the detection limit. The results are compared to ab-initio theory. Calculated equilibrium positions of adatoms and their host structure show strong relaxation effects. d-shell occupancies and magnetic properties are extracted. Moreover, we present simulated resonant spectral shapes.

[1] Y. L. Chen et al., Science 329, 659 (2010).