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HL: Fachverband Halbleiterphysik

HL 105: Transport: Majorana fermions (TT with DS/HL/MA/O)

HL 105.2: Vortrag

Freitag, 20. März 2015, 09:45–10:00, H 0104

Topological phases in magnetic adatom-chains on top of a Rashba superconducting surface — •Andreas Heimes, Daniel Mendler, and Panagiotis Kotetes — Institut für Theoretische Festkörperphysik, Karlsruher Institut für Technologie, 76131 Karlsruhe

We investigate a Majorana fermion (MF) platform consisting of a chain of magnetic adatoms placed on top of a conventional superconductor with Rashba spin-orbit coupling. By identifying the classical magnetic ground state of the adatom chain, we extract a phase diagram which exhibits ferromagnetic (FM), antiferromagnetic (AFM) as well as spiral orders. We determine the parameter regime for which the FM or AFM phases dominate over the spiral and perform a topological analysis of the low-energy electronic spectrum. To this end we derive an effective model relying on Shiba bound states. We find that for both magnetic patterns, FM and AFM, the hybrid system behaves as a topological superconductor which can harbor one or even two MFs per edge. We propose directions on how to experimentally access these different MF phases.