Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 23: Topological Insulators I (jointly with MA, DS, O, TT)

HL 23.2: Talk

Monday, March 26, 2012, 18:00–18:15, H 1012

In-plane anisotropy of Fe atoms on Bi₂Se₃(111) — J. Honolka¹, A. A. Khajetoorians², V. Sessi³, T. O. Wehling⁴, S. Stepanow¹, J. Mi⁵, B. B. Iversen⁵, •T. Schlenk², J. Wiebe², N. Brookes³, A. I. Lichtenstein⁴, P. Hofmann⁵, K. Kern¹, and R. Wiesendanger² — ¹Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, 70569 Stuttgart, Germany — ²Institute for Applied Physics, Universität Hamburg, D-20355 Hamburg, Germany — ³ESRF, Grenoble, France — ⁴1. Institut für Theoretische Physik I, Universität Hamburg, D-20355 Hamburg, Germany — ⁵Interdisciplinary Nanoscience Center, Aarhus University, Denmark

Topological insulators exhibit a linearly dispersing gapless topological surface state where both the spin and momentum degrees of freedom are locked. The topological nature of this state results in interesting effects such as suppression of back-scattering. Recently, the robustness of these surface states against magnetic order has been investigated intensively. Here, we explore the magnetic properties of single Fe adatoms on the Bi₂Se₃ surface, in the coverage range < 1% , with combined non-local x-ray magnetic circular dichroism techniques and local low temperature scanning tunneling spectroscopy. We show that the Fe adatoms relax into the surface and exhibit a magnetic easy axis within the surface-plane, contrary to recent reports. Futhermore, we show how ab-initio approaches can give a reorientation of the easy axis from out-of-plane to in-plane when considering the interplay of Coulomb interactions, spin orbit coupling, and dynamic hybridization effects.