PHOTON-ASSISTED TUNNELING THROUGH A QUANTUM-DOT

We study single-electron tunneling in a two-junction device in the presence of microwave radiation. We introduce a model for numerical simulations that extends the Tien-Gordon theory for photon-assisted tunneling to encompass correlated single-electron tunneling. We predict sharp current jumps which reflect the discrete photon energy hf, and a zero-bias current whose sign changes when an electron is added to the central island of the device. Measurements on split-gate quantum dots show microwave-induced features that are in good agreement with the model.