TY  - JOUR
AU  - Peixoto, Thiago R. F.
AU  - Bentmann, Hendrik
AU  - Rüßmann, Philipp
AU  - Tcakaev, Abdul-Vakhab
AU  - Winnerlein, Martin
AU  - Schreyeck, Steffen
AU  - Schatz, Sonja
AU  - Vidal, Raphael Crespo
AU  - Stier, Fabian
AU  - Zabolotnyy, Volodymyr
AU  - Green, Robert J.
AU  - Min, Chul Hee
AU  - Fornari, Celso I.
AU  - Maaß, Henriette
AU  - Vasili, Hari Babu
AU  - Gargiani, Pierluigi
AU  - Valvidares, Manuel
AU  - Barla, Alessandro
AU  - Buck, Jens
AU  - Hoesch, Moritz
AU  - Diekmann, Florian
AU  - Rohlf, Sebastian
AU  - Kalläne, Matthias
AU  - Rossnagel, Kai
AU  - Gould, Charles
AU  - Brunner, Karl
AU  - Blügel, Stefan
AU  - Hinkov, Vladimir
AU  - Molenkamp, Laurens W.
AU  - Reinert, Friedrich
TI  - Non-local effect of impurity states on the exchange coupling mechanism in magnetic topological insulators
JO  - npj quantum materials
VL  - 5
IS  - 1
SN  - 2397-4648
CY  - [London]
PB  - Nature Publishing Group
M1  - FZJ-2020-04720
SP  - 87
PY  - 2020
AB  - Since the discovery of the quantum anomalous Hall (QAH) effect in the magnetically doped topological insulators (MTI) Cr:(Bi,Sb)2Te3 and V:(Bi,Sb)2Te3, the search for the magnetic coupling mechanisms underlying the onset of ferromagnetism has been a central issue, and a variety of different scenarios have been put forward. By combining resonant photoemission, X-ray magnetic circular dichroism and density functional theory, we determine the local electronic and magnetic configurations of V and Cr impurities in (Bi,Sb)2Te3. State-of-the-art first-principles calculations find pronounced differences in their 3d densities of states, and show how these impurity states mediate characteristic short-range pd exchange interactions, whose strength sensitively varies with the position of the 3d states relative to the Fermi level. Measurements on films with varying host stoichiometry support this trend. Our results explain, in an unified picture, the origins of the observed magnetic properties, and establish the essential role of impurity-state-mediated exchange interactions in the magnetism of MTI.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000590981700001
DO  - DOI:10.1038/s41535-020-00288-0
UR  - https://juser.fz-juelich.de/record/888146
ER  -