Dresden 2020 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 2: Topological Insulators 1 (jointly with DS, MA, HL, O) (joint session TT/HL)

HL 2.9: Talk

Monday, March 16, 2020, 11:45–12:00, HSZ 03

MBE-grown Sb₂Te₃/Bi₂Te₃ heterostructures - Tuning of the topological surface states — Vanda M. Pereira, Chi-Nan Wu, Liu Hao Tjeng, and •Simone G. Altendorf — Max Planck Institute for Chemical Physics of Solids, Dresden, Germany

Topological insulators (TIs) are bulk insulators with the bulk band gap only intersected by conducting, Dirac-cone like surface states that are topologically protected. For many materials, the Dirac point of these surface states lays buried in the bulk bands which hinders an experimental observation of the various theoretically predicted topological quantum effects, like the quantum anomalous Hall effect.

In our study, we combine two TIs, namely Sb₂Te₃ and Bi₂Te₃, in a heterostructure which allows for a tuning of the position of the Dirac point to the Fermi level by varying the layer thicknesses. Using the optimized layer structure, we investigate the changes of the TI properties when interfaced with a magnetic substrate. We will present a characterization of the MBE-grown Sb₂Te₃/Bi₂Te₃ heterostructures on non-magnetic and magnetic substrates by RHEED, XPS, ARPES, XMCD, and transport measurements.