Berlin 2024 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 10: Focus Session: Evolution of Topological Materials into Superconducting Nanodevices I (joint session HL/TT)
HL 10.7: Vortrag
Montag, 18. März 2024, 16:45–17:00, EW 202
Topology of finite size magnetic topological insulator/superconductor heterostructures — •Julian Legendre1, Eduárd Zsurka1,2,3, Daniele Di Miceli1,4, Llorenç Serra4,5, Kristof Moors2,3, and Thomas L. Schmidt1 — 1Department of Physics and Materials Science, University of Luxembourg — 2PGI-9, Forschungszentrum Jülich — 3JARA-Fundamentals of Future Information Technology, Jülich-Aachen Research Alliance, Forschungszentrum Jülich and RWTH Aachen University — 4Institute for Cross-Disciplinary Physics and Complex Systems IFISC (CSIC-UIB) — 5Department of Physics, University of the Balearic Islands
Heterostructures of magnetic topological insulators (MTIs) and superconductors (SCs) in two-dimensional (2D) slab and one-dimensional (1D) nanoribbon geometries have been predicted to host chiral Majorana edge states or Majorana bound states (MBS), respectively. We study the topological properties of such MTI/SC heterostructures upon variation of the slab geometry from wide slabs to quasi-1D nanoribbon systems and as a function of the chemical potential, the magnetic doping, and the induced superconducting pairing potential. To do so, we construct effective symmetry-constrained low-energy k · p Hamiltonians accounting for the real-space confinement. Transitions between topological phases are then signalled by sign changes of the resulting gap magnitude at the Γ point. For confined slab geometries, as the chemical potential, the magnetic doping and/or the width of the slab are varied, we observe a periodic sign change of the bulk gap, which entails reentrant MBS at the ends of the nanoribbon.