Persistent current in mesoscopic semiconductor rings: A two-band model

In the framework of the two-band model, we calculate the persistent current I for mesoscopic semiconductor rings determined from the Aharonov-Bohm effect (AB). This current is periodic in ΦP with periodicity Φ₀ = hc/e. In particular, it is indicated that the interband coupling enhances the current while the impurity suppresses the current. More 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.