Fano Resonance in a Quantum Wire with a Side-coupled Quantum Dot

Kensuke Kobayashi, Hisashi Aikawa, Akira Sano, Shingo Katsumoto, Yasuhiro Iye

Published 2003-11-21, updated 2004-08-01Version 2

We report a transport experiment on the Fano effect in a quantum connecting wire (QW) with a side-coupled quantum dot (QD). The Fano resonance occurs between the QD and the "T-shaped" junction in the wire, and the transport detects anti-resonance or forward scattered part of the wavefunction. While in this geometry it is more difficult to tune the shape of the resonance than in the previously reported Aharonov-Bohm-ring type interferometer, the resonance purely consists of the coherent part of transport. By utilizing this advantage, we have qualitatively explained the temperature dependence of the Fano effect by including the thermal broadening and the decoherence. We have also proven that this geometry can be a useful interferometer to measure the phase evolution of electrons at a QD.