ORBITAL MAGNETISM IN ENSEMBLES OF PARABOLIC POTENTIALS

We study the magnetic susceptibility of an ensemble of noninteracting electrons confined by parabolic potentials and subjected to a perpendi cular magnetic field at finite temperatures. We show that the behavior of the average susceptibility is qualitatively different from that of billiards. When averaged over the Fermi energy the susceptibility exh ibits a large paramagnetic response only at certain special field valu es, corresponding to commensurate classical frequencies, being negligi ble elsewhere. We derive approximate analytical formulas for the susce ptibility and compare the results with numerical calculations. [S1063- 651X(98)04110-5].