Mesoscopic Fano Effect throughaQuantumDotinanAharonov-BohmRing (original) (raw)

The Fano effect illustrates how the interference and resonance cooperatively occur between a discrete state and a continuum energy state. We have realized a tunable Fano system by fabricating a quantum dot embedded in an Aharonov-Bohm ring on a 2DEG. In the Coulomb oscillation, clear asymmetric lineshapes were observed, which manifest the formation of the Fano state, namely, a mixture of the discrete state and the continuum state. The non-equilibrium transport and the temperature dependence reveal the essential role of the coherence for this effect. Through the phase controlling by the magnetic flux piercing the ring, Fano's asymmetric parameter q is obtained as a complex number for the first time.