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TT: Fachverband Tiefe Temperaturen
TT 15: Quantum Transport and Quantum Hall Effects I (joint session HL/TT)
TT 15.4: Talk
Monday, March 27, 2023, 15:45–16:00, JAN 0027
Selective scattering between counter-propagating edge states in a topological insulator — •Meng Hao1,2, Li-Xian Wang1,2, Fabian Schmitt1,2, Hartmut Buhmann1,2, and Laurens W. Molenkamp1,2 — 1Institute for Topological Insulators, Würzburg, Germany — 2Physikalisches Institut (EP III) Würzburg University, Würzburg, Germany
The quantum Hall state, known by its dissipationless nature, comprises chiral edge states in a two-dimensional electron gas (2DEG). In the ordinary quantum Hall effect, all edge states propagate in the same direction, populated equally. Thus, they are immune to inter-edge-state scattering. In contrast, counter-propagating edge states, populated unequally, are naturally sensitive to the scattering process. However, a realization of this scenario so far was only possible by stacked layers of high-mobility 2DEGs, e.g., quantum wells or graphene. Here we realize the counter-propagating edge states in a three-dimensional topological insulator controlled by top and bottom gates. Surprisingly, the counter-propagating edge states prove to scatter into each other selectively. Our first attempt shows that this inter-edge-state scattering occurs exclusively between Landau levels with the same Landau index. We further propose a cross bar equipped with split-gates to determine the selection rule of scattering and scattering parameters unambiguously. Following this proposal, we will show some preliminary results and report our experimental advances.