| Summary: | 碩士 === 臺灣大學 === 物理研究所 === 98 === The generalized Floquet approach is extended to sutdy the memory effect beyond the wide band limit on the photon-assisted electron tunneling through a periodically driven single quantum dot. An analytical Tien-Gordon-like expression, including the memory effect, for the current and transmission coefficient is derived based on the generalized Van Vleck (GVV) nearly degenerate perturbation theory. As a result, multiphoton (MP) coherent
destruction of tunneling (CDT) phenomenon for small bias voltage is predicted by the transmission coefficients for the respective scattering channels. Numerically converged simulations and GVV analytical results are compared and both reveal that the memory effect leads to the suppression of the d.c. current stair-step jumps when varying the bias voltage on the single quantum dot. Furthermore, a novel blockade phenomenon that does not exist in the wide band limit is observed when the memory effect becomes significant, showing that the pumped current oscillate distinctively with respect to the gate voltage in the in the large bias limit. Finally, analytical expressions are obtained in the wide band limit, showing the temperature dependence of the conductance and current.
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