Numerical Corner and hinge states in higher-order topological insulators: Floquet engineering and coupled layer construction
Speaker: Kirill Plekhanov (University of Basel, J. Klinovaja group)
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Title: NCorner and hinge states in higher-order topological insulators: Floquet engineering and coupled layer construction
Speaker: GHE Fellow K. Plekhanov (University of Basel, J. Klinovaja group)
Date: November 14th 2019 @ 2pm
Place: Albert Ludwigs University Freiburg (Hörsaal II, Physik Hochhaus, 1. OG, Hermann-Herder-Str. 3, 79104 Freiburg)
We propose several protocols to generate higher-order topological insulators in 2D and 3D. First, we consider a Floquet triple-layer setup composed of a 2D electron gas with spin-orbit interactions, proximity coupled to an s-wave superconductor and to a ferromagnet driven at resonance. The ferromagnetic layer generates a time-oscillating Zeeman field which competes with the induced superconducting gap and leads to a topological phase transition. The resulting Floquet states support a 2-nd order topological superconducting phase in 2D with a pair of localized zero-energy Floquet Majorana corner states. Second, we consider a system of tunnel-coupled 2D electron and hole-gas layers with Rashba spin-orbit interactions stacked along a given axis. The heterostructure is subjected to a spatially alternating Zeeman field. The interplay of the intra-layer tunnel couplings and the Zeeman field generates a topological phase diagram which hosts a 2-nd order topological insulator phase in 3D. The emergence of the topological phases is proven analytically and confirmed by numerical simulations. The topological phases are stable against disorder and parameter variations and are within experimental reach.