RESONANT-TUNNELING THROUGH 2 DISCRETE ENERGY-STATES

We observed new type of Lorentzian-shaped resonances in the current through two coupled quantum dots with tunable barriers. We show that the resonances occur when the energy of two discrete states match. Their widths can be as small as 5 μeV and are only determined by the lifetime of the discrete energy states, independent of the reservoir temperature. The achieved energy resolution makes it possible to observe a small asymmetric deviation from the Lorentzian line shape, which we attribute to inelastic tunnel processes. © 1995 The American Physical Society.