Photon-Assisted Tunneling Through a Quantum Dot: Theory and Experiment
We have studied the effect of microwaves on Coulomb blockade devices, both theoretically and experimentally. Our model extends the Tien-Gordon theory for photon-assisted tunneling to encompass the correlated tunneling of electrons through small capacitance double-junction devices. The main theoretical results for a double-junction system are (1) the prediction of sharp current jumps reflecting the discrete photon energy hf in current-gate voltage characteristics and (2) the prediction of a zero-bias current whose sign changes when an electron is added to the island between the junctions. Preliminary measurements are presented on split-gate quantum dots with 19 GHz microwaves applied to one of the control gates. The observed photoresponse is in good agreement with the predictions of the model.
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