Quantum interference of electrons in multiwall carbon nanotubes

In magnetoresistance measurements of a single multiwall carbon nanotube we have observed the periodic oscillation which increases in amplitude below 3 0 K. The period has the angular dependence of 1/cos theta, theta being the angle between the nanotube axis and magnetic field, and it corresponds to t he field that the magnetic flux penetrating a nanotube equals one-third of a Bur quanta, h/3e. The observation is explained in terms of the Aharonov-B ohm effect for three coexisting nanotubes with different chiralities. [S016 3-1829(99)12643-2].