PERSISTENT CURRENT IN MESOSCOPIC SEMICONDUCTOR RINGS - A 2-BAND MODEL

In the framework of the two-band model, we calculate the persistent cu rrent I for mesoscopic semiconductor rings determined from the Aharono v-Bohm effect (AB). This current is periodic in Phi with periodicity P hi(0) = hc/e. In particular, it is indicated that the interband coupli ng enhances the current while the impurity suppresses the current. Mor e intriguingly, it has also been shown that there exists a spontaneous AB flux for a clean ring with an even number of electrons, and for a dirty ring with an odd number of electrons.