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Majorana modes in emergent-wire phases of helical and cycloidal magnet-superconductor hybrids

Rex, Stefan; Gornyi, Igor V.; Mirlin, Alexander D.

Abstract (englisch):
Noncollinear magnetism opens exciting possibilities to generate topological superconductivity. Here, we focus on helical and cycloidal magnetic textures in magnet-superconductor hybrid structures in a background magnetic field. We demonstrate that this system can enter a topological phase which can be understood as a set of parallel topological wires. We explore and confirm this idea in depth with three different approaches: a continuum model, a tight-binding model based on the magnetic unit cell, and exact diagonalization on a finite two-dimensional lattice. The key signature of this topological state is the presence of Majorana bound states at certain disclination defects in the magnetic texture. Based on the C2 symmetry imposed by the helical or cycloidal texture, we employ the theory of topological crystalline superconductors with rotation invariants to obtain the Majorana parity at disclinations. Furthermore, we consider a 90-deg helimagnet domain wall, which is formed by a string of alternating disclinations. We discuss how the resulting chain of disclination bound states hybridizes into two chiral modes with different velocities. ... mehr

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Originalveröffentlichung
DOI: 10.1103/PhysRevB.102.224501
Zugehörige Institution(en) am KIT Institut für Quantenmaterialien und -technologien (IQMT)
Institut für Theorie der Kondensierten Materie (TKM)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2020
Sprache Englisch
Identifikator ISSN: 2469-9950, 2469-9969
KITopen-ID: 1000127297
HGF-Programm 43.21.01 (POF III, LK 01) Quantum Correlations in Condensed Matter
Erschienen in Physical review / B
Verlag American Physical Society (APS)
Band 102
Heft 22
Seiten 224501
Vorab online veröffentlicht am 01.12.2020
Nachgewiesen in Web of Science
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