Controllable 0-π transition in the superconductor/carbon nanotube quantum dot/superconductor junction by an axial magnetic field

The supercurrent flowing through the superconductor/carbon nanotube quantum dot/superconductor junction has been investigated. It shows that the direction of the supercurrent can be controlled by a small axial magnetic field, leading to the 0-π transition, due to the electron's large orbital magnetic moment in the carbon nanotubes.