抄録
We study the persistent current (PC) in one-dimensional (1D) magnetic-flux threaded mesoscopic rings, which is constructed according to the random-dimer (RD) model. It is found that the PC varies significantly when the Fermi energy is changed in the system. The PC can approach the behaviour of free electrons regardless of the disorder if there is the extended electronic state at the Fermi level; while the PC can be depressed dramatically if the highest-occupied electronic state is localized or in the intermediate case between the extended state and localized one. This property provides a possible explanation to the anomalously large PC observed in some experiments. Furthermore, it is demonstrated that the electronic delocalization leads to unsuppressed persistent currents and \\sqrtN unscattered states exist around the resonant energy in the RD model from the viewpoint of the PC. The possibility to use 1D random-dimer mesoscopic rings as quantum-switch devices is also discussed.
