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[6]Investigation of the Quantum Transport Characteristics of Some Nanodevices:
The conductance and the time-averaged current of a quantum dot turnstile device in which two tunnel barriers are modulated by radio-frequency (rf) signals of frequency f are investigated. The quantum dot is coupled to two superconducting reservoirs via two asymmetric tunnel barriers. The effect of the Coulomb blockade is taken into consideration. Also, Aharonov-Bohm effect is studied for such a quantum dot turnstile embedded in one of the arm of a ring. Both conductance and current depend on the gate voltage, frequency of rf-signal, the dimensions of the device and the temperature. A conductance oscillation is obtained. It was also found that the quantized current plateau modified by quantum interference, due to Andreev reflection processes, depends on the different parameters considered in our model. Our results show that the present model could be operated as electron turnstile device at very high frequency in the THz range.
