Chiral symmetries and Majorana fermions in coupled magnetic atomic chains on a superconductor

Abstract

We study the magnetic structures and their connections with topological superconductivity due to proximity effect for coupled magnetic atomic chains deposited on a superconductor. Several magnetic phases are self-consistently determined, including both the coplanar and non-coplanar ones. For a $N$-chain triangular atomic ladder, topologically nontrivial superconducting states can always be realized, but strongly depend on its magnetic structure and the number of atomic chains. When $N$ is even, the topologically nontrivial states with noncoplanar structures are characterized by ${\mathbb{Z}}_2$ invariants, while the topologically nontrivial noncoplanar states with an odd $N$ are characterized by integer $\mathbb{Z}$ invariants, due to the presence of a new chiral symmetry. The new chiral symmetry for the noncoplanar states is found to be robust against the on-site disorder, as long as the crystal reflection symmetry is respected.

13 pages, 12 figures and 2 tables

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Cited by in corpus (11)

• Synthetic Weyl Points and Chiral Anomaly in Majorana Devices with Nonstandard Andreev-Bound-State Spectra
• Aspects of topological superconductivity in 2D systems: noncollinear magnetism, skyrmions, and higher-order topology
• Topological Superconductivity Induced by Magnetic Texture Crystals
• Nodal Andreev Spectra in Multi-Majorana Three-Terminal Josephson Junctions
• Magnetoelectrically-Tunable Andreev-Bound-State Spectra and Spin Polarization in P-Wave Josephson Junctions
• Topological superconductivity in a magnetic-texture coupled Josephson junction
• Magnetic flux induced topological superconductivity in magnetic atomic rings
• Topological phase transitions in superconductors with chiral symmetry
• Magnetic flux induced higher-order topological superconductivity
• Boundary states in the chiral symmetric systems with a spatial symmetry
• Odd-frequency Pairing in Josephson Junctions Coupled by Magnetic Textures