Freiburg 2019 – wissenschaftliches Programm
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FM: Fall Meeting
FM 63: Poster: Enabling Technologies: Quantum Materials, Quantum Dots, Quantum Wires, Point Contacts and Superconducting Systems
FM 63.22: Poster
Mittwoch, 25. September 2019, 16:30–18:30, Tents
Anomalous and topological Hall effect in magnetically doped topological insulator thin films — •Gertjan Lippertz1,2, Andrea Bliesener1, Alexey Taskin1, Lino Pereira2, and Yoichi Ando1 — 1Institute of Physics II, University of Cologne, Germany — 2Instituut voor Kern- en Stralingsfysica, KU Leuven, Belgium
Breaking TRS in a topological insulator (TI) by magnetic doping opens an energy gap at the Dirac point on the top and bottom surface. Thin films of this kind of gapped topological insulator exhibit new quantum phenomena, including the quantum anomalous Hall effect (QAHE), where spontaneous magnetization leads to a dissipationless spin-polarised edge channel and a quantized Hall resistance of h/e2 [1]. Furthermore, an additional topological Hall component has recently been observed in such samples, possibly originating from the formation of Skyrmions [2].
Here we report on our observation of the anomalous and topological Hall effect in V- and Cr-doped (BixSb1−x)2Te3 films grown by MBE. We will show how a gradient in the Bi/Sb ratio along the growth direction leads to a broken inversion symmetry and the appearance of an additional topological Hall component at the coercive field. Uniform samples on the other hand show the usual anomalous Hall effect close to the quantized Hall resistance of h/e2.
References:
[1] C.-Z. Chang et al., Nature Materials 14, 473-477 (2015)
[2] K. Yasuda et al., Nature Physics 12, 555-559 (2016)