We investigate the possibility of realizing a topological state in the impurity band formed by a chain of classical spins embedded in a two-dimensional singlet superconductor with Rashba spin-orbit coupling. In contrast to similar proposals which require a helical spin texture of the impurity spins for a nontrivial topology, here we show that spin-flip correlations due to the spin-orbit coupling in the superconductor produces a topological state for ferromagnetic alignment of the impurity spins. From the Bogoliubov-de Gennes equations we derive an effective tight-binding model for the subgap states which resembles a spinless superconductor with long-range hopping and pairing terms. We evaluate the topological invariant, and show that a topologically non-trivial state is generically present in this model.
@article{arxiv.1407.6345,
title = {Topological Yu-Shiba-Rusinov chain from spin-orbit coupling},
author = {P. M. R. Brydon and S. Das Sarma and Hoi-Yin Hui and Jay D. Sau},
journal= {arXiv preprint arXiv:1407.6345},
year = {2015}
}