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Interplay of topological phases in magnetic adatom-chains on top of a Rashba superconducting surface

Heimes, Andreas; Mendler, D.; Kotetes, P.

We investigate the topological properties and the accessible Majorana fermion (MF) phases arising in a hybrid device consisting of a chain of magnetic adatoms placed on the surface of a conventional superconductor with Rashba spin–orbit coupling (SOC). By identifying the favored classical magnetic ground state of the adatom chain, we extract the corresponding phase diagram which exhibits an interplay of ferromagnetic (FM), antiferromagnetic (AFM) and spiral orders. We determine the parameter regime for which the FM or AFM phases dominate over the spiral and additionally become stable against thermal and quantum fluctuations. For the topological analysis we focus on the FM and AFM cases and employ a low-energy effective model relying on Shiba bound states. We find that for both magnetic patterns the hybrid system behaves as a topological superconductor which can harbor one or even two MFs per edge, due to chiral symmetry. As we show, the two magnetic orderings lead to qualitatively and quantitatively distinct topological features that are reflected in the spatial profile of the MF wavefunctions. Finally, we propose directions on how to experimentally access the diverse MF phases by varying the adatom spacing, the SOC strength, or the magnetic moment of the adatoms in consideration.

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Verlagsausgabe §
DOI: 10.5445/IR/1000046769
DOI: 10.1088/1367-2630/17/2/023051
Zitationen: 30
Web of Science
Zitationen: 30
Zugehörige Institution(en) am KIT Institut für Theoretische Festkörperphysik (TFP)
Publikationstyp Zeitschriftenaufsatz
Jahr 2015
Sprache Englisch
Identifikator ISSN: 1367-2630
KITopen-ID: 1000046769
Erschienen in New journal of physics
Band 17
Seiten 023051
Bemerkung zur Veröffentlichung Gefördert durch den KIT-Publikationsfonds
Nachgewiesen in Scopus
Web of Science
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