Majorana fermions from Shiba states in an antiferromagnetic chain on top of a superconductor (original) (raw)

We propose a new Majorana fermion platform based on an antiferromagnetically ordered chain of atoms in proximity to a conventional superconductor. This hybrid system can be driven into a topologically non-trivial phase by the combination of a supercurrent flow and a weak Zeeman field. Both can be finely tuned providing a platform with enhanced functionality for applications. Remarkably, the electronic spin-polarization of the arising edge Majorana fermions depends on the parity of the number of magnetic moments. The resulting even-odd effect should be measurable and could serve as a signature of the Majorana fermions. We introduce the basic concepts on a model level and confirm them by a microscopic analysis. * Electronic address: andreas.heimes@kit.edu Figure 1: Antiferromagnetic chain on top of a superconductor. A single spin-filtered MF appears at each edge in the simultaneous presence of a weak in-plane Zeeman-field B (yzplane) and a supercurrent flow J (z-axis). Inset: Mapping to Kitaev's model with unpaired MFs γnA,B.