Dresden 2020 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 30: Poster I
HL 30.34: Poster
Dienstag, 17. März 2020, 13:30–15:45, P3
Anomalous and topological hall effect in magnetically-doped topological insulator thin films grown by molecular beam epitaxy — •Anjana Uday1, Gertjan Lippertz1,2, Andrea Bliesner1, Alexey Taskin1, and Yoichi Ando1 — 1Physics Institute II, University of Cologne, Germany — 2Quantum Solid State Physics, KU Leuven, Belgium
There is an increasing demand for magnetic topological quantum materials in recent years as such materials offer a productive platform for the development of next-generation spintronic devices. When a topological insulator (TI) is magnetically doped, the breaking of time reversal symmetry (TRS) opens up an energy gap at the Dirac point of the surface states. Furthermore, a remarkable quantum phenomenon known as the quantum anomalous Hall effect (QAHE) is observed in such materials when their fermi level is tuned into this exchange gap. When the QAHE is realized, the spontaneous magnetization leads to a dissipationless spin-polarised edge channel, giving rise to a quantized Hall resistance of h/e2. An additional topological Hall component has recently been observed in such samples, possibly originating from the formation of Skyrmions. Our observation of the anomalous and topological Hall effect in V- and Cr-doped (BixSb(1−x))2Te3 films grown by MBE 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 near the coercive field while homogeneous samples exhibit the usual anomalous Hall effect close to the quantized Hall resistance of h/e2.