PERSISTENT CURRENT IN MESOSCOPIC SEMICONDUCTOR RINGS AT EXTREMELY LOW-TEMPERATURES - 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) at zero temperature. This current is periodic in Ph i with the periodicity of Phi(0) = hc/e. In particular, it is indicate d that the interband coupling enhances the current while the impurity suppresses the current. More intriguingly, it has also been shown that there exists the spontaneous AB flux for a clean ring with even numbe r of electrons; while for a dirty ring with odd number of electrons.