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arXiv · 1510.08308

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

Jinpeng Xiao·Jin An
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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.

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Jinpeng Xiao, Jin An. 2015-10-28. Chiral symmetries and Majorana fermions in coupled magnetic atomic chains on a superconductor. https://doi.org/10.1088/1367-2630%2F17%2F11%2F113034

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