Topological superconducting state and Majorana fermions in carbon nanotubes

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.