AHARONOV-BOHM OSCILLATIONS AT FINITE-TEMPERATURE

The Aharonov-Bohm effect is the quantum interference of charged partic les in mesoscopic rings enclosing a magnetic held. The wavefunction ac quires a phase due to the field flux phi and gives rise to flux-depend ent oscillations in persistent charge currents. The period and amplitu de of the oscillations are associated with the properties of the Fermi surface of the elementary excitations. For systems with one Fermi sur face the groundstate persistent current has the form of a saw-tooth. T he temperature reduces the amplitudes of oscillation by smearing the F ermi surface. The amplitude of higher harmonics decreases faster with T than the fundamental one, changing the saw-tooth to a more sinusoida l form with much smaller amplitude. The controlling parameter is LT/zv (F), where L is the length of the ring, v(F) is the Fermi velocity and z the dressed generalized charge. Our calculations are performed with in the framework of Bethe's ansatz. (C) 1996 American Institute of Phy sics.