Mesoscopic transport through a quantum-dot-embedded Aharonov-Bohm ring threaded with ac flux

The electron transporting through a mesoscopic ring embedded with one quant um dot and threaded by de and ac magnetic fluxes is investigated by employi ng the Keldysh nonequilibrium Green function technique. The tunneling curre nt and differential conductance are derived to show the Aharonov-Bohm-like effect induced by external magnetic fluxes. The multi-channel ring and mult i-level quantum dot system is studied. The quenching and nonmonotone effect s versus the magnitude of ac flux are revealed in differential conductance. This signifies that at some values of ac flux, the tunneling current may b e suppressed or enhanced. The differential conductance oscillation and I-V characteristics are studied numerically at zero temperature. The aperiodica lly nonmono-tonical conductance versus the magnitude of ac flux, multi-chan nel negative differential conductance, photon-electron pump effect are also observed.