Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 32: Focus Session: Chiral Topological Superconductors and Majorana Fermions

TT 32.3: Hauptvortrag

Dienstag, 13. März 2018, 10:30–11:00, H 0104

Towards the Design of Majorana Bound States in Artificially Constructed Magnetic Atom Chains on Elemental Superconductors — •Roland Wiesendanger — Dept. of Physics, University of Hamburg, Hamburg, Germany

We demonstrate the fully-controlled bottom-up fabrication of artificial 1D atomic chains from individual magnetic Fe adatoms on high spin-orbit coupled superconducting Re(0001) substrates by STM-based atom-manipulation techniques at T=350 mK. Spin-polarized STM measurements indicate the presence of non-collinear spin textures, i.e. spin spiral ground states, stabilized by interfacial Dzyaloshinskii-Moriya interactions. Tunneling spectra measured spatially resolved on the Fe-atom chain on Re(0001) reveal the evolution of the local density of states inside the superconducting gap as well as the development of zero-energy bound states at the ends of the chain, which are distinguishable from trivial end states by systematically increasing the number of atoms within the Fe-atom chain. The experimental results will be compared with model-type calculations supporting the interpretation of the spectroscopic signatures at the ends of the chains as Majorana bound states. Such Majorana states can encode topological qubits and ultimately provide a new direction in topological quantum computation.