THE EFFECT OF GATE ON PERSISTENT CURRENT IN MESOSCOPIC OPEN RING

Abstract

The transport property of electrons in a mesoscopic ring with one arm subject to gate is investigated through the quantum waveguide theory. The persistent current is produced and controlled by tuning the strength of potential energy even in the absence of magnetic field. The persistent current can not only be observed if one tunes the Fermi energy nearing the antiresonance or the Fano resonance of the transport current in the weak strength of potential energy, but also can be detected at the resonance of the transport current in the strong strength of potential energy. An impurity is embedded in the right lead of the ring was also investigated and the large persistent current can be produced by varying the strength of the impurity potential and the length between the impurity and ring.