Majorana fermions emerging from magnetic nanoparticles on a superconductor without spin-orbit coupling

TL;DR

This paper proposes a new system of magnetic nanoparticles on a superconductor that can host Majorana fermions without requiring spin-orbit coupling, expanding possibilities for topological quantum computing.

Contribution

It introduces a one-dimensional magnetic nanoparticle chain on a superconductor as an alternative platform for Majorana fermions, eliminating the need for spin-orbit coupling.

Findings

Topological transition identified in the nanoparticle chain

Majorana fermions localized at chain ends

Disorder effects on topological states analyzed

Abstract

There exists a variety of proposals to transform a conventional s-wave superconductor into a topological superconductor, supporting Majorana fermion mid-gap states. A necessary ingredient of these proposals is strong spin-orbit coupling. Here we propose an alternative system consisting of a one-dimensional chain of magnetic nanoparticles on a superconducting substrate. No spin-orbit coupling in the superconductor is needed. We calculate the topological quantum number of a chain of finite length, including the competing effects of disorder in the orientation of the magnetic moments and in the hopping energies, to identify the transition into the topologically nontrivial state (with Majorana fermions at the end points of the chain).