Regensburg 2019 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 3: Topological Insulators (joint session TT/MA)
TT 3.6: Vortrag
Montag, 1. April 2019, 10:45–11:00, Theater
Transport properties of MBE grown Bi2Te3 on Fe3O4 thin film heterostructure — •Chi-Nan Wu1,2, Vanda M. Pereira1, Cariad Knight1,3, Simone G. Altendorf1, Minghwei Hong4, Jueinai Kwo2, and Liu Hao Tjeng1 — 1MPI CPfS, Dresden, Germany — 2Dept. of Phys., NTHU, Hsinchu, Taiwan — 3UBC, Vancouver, Canada — 4Dept. of Phys., NTU, Taipei, Taiwan
Quantum anomalous Hall effect (QAHE) is expected to be observed when magnetic ordering is introduced in a topological insulator (TI) system. This effect is due to time reversal symmetry breaking and can be experimentally achieved by doping transition metals into the TI or by using the magnetic proximity effect (MPE) in TI/ferromagnetic insulator (FI) heterostructures to magnetize the topological surface state (TSS) at the interface. The MPE in TI/FIs has the advantage of less defects in the TI, and it might have a higher Tc to exhibit the QAHE. However, the QAHE has not yet been experimentally observed for TI/FI heterostructures. We have successfully grown heterostructures of Bi2Te3/Fe3O4 thin films by molecular beam epitaxy with minimum chemical reaction at the interface which is crucial for the short ranged MPE. In order to study the MPE induced gap opening of the TSSs, we conducted electrical transport measurements. The temperature dependent resistance shows a sharp Verwey transition of Fe3O4 at 122K indicating very good quality of the FI layer. From magnetoresistance measurement at low temperature, we observed the suppression of the weak antilocalization in the TI layer, indicating a TSS gap opening by the MPE.