Majorana fermions in carbon nanotubes

TL;DR

This paper proposes that carbon nanotubes can host one-dimensional topological superconductivity with Majorana fermions at their ends, enabled by curvature-induced spin-orbit coupling and broken chirality symmetry, leading to a potential robust topological gap.

Contribution

It introduces a novel mechanism for topological superconductivity in CNTs mediated by curvature-induced spin-orbit coupling and broken chirality symmetry.

Findings

Topological gap of around 500 mK is achievable in CNTs.

Majorana fermions can be localized at nanotube ends.

Topological state is robust with realistic parameters.

Abstract

We show that carbon nanotubes (CNT) are good candidates for realizing one-dimensional topological superconductivity with Majorana fermions localized near the end points. The physics behind topological superconductivity in CNT is novel and is mediated by a recently reported curvature-induced spin-orbit coupling which itself has a topological origin. In addition to the spin-orbit coupling, an important new requirement for a robust topological state is broken chirality symmetry about the nanotube axis. We use topological arguments to show that, for recently realized strengths of spin-orbit coupling and broken chirality symmetry, a robust topological gap of around 500 mK is achievable in carbon nanotubes.