MAGNETIC-ORDERING TRANSITION OF ELECTRONS ON MESOSCOPIC TUBES

We find a paramagnetic to diamagnetic ordering transition of a two-dimensional electron gas on a mesoscopic tube in a magnetic field as the tube radius is varied. Spin effects (Pauli paramagnetism) are explicitly considered. The dependence of magnetization on temperature is calculated. A relationship between the periodicity of the magnetization and the de Haas-van Alphen oscillations is presented. These results are directly pertinent to the recently synthesized helical microtubules of graphite.