0.7 Anomaly Induced by Fano Resonance in Quantum Point Contact Coupled with Quantum Dot

The conductance through a quantum point contact (QPC) when a quantum dot (QD) is coupled to the side of a QPC channel is studied. It is experimentally demonstrated that a 0.7 conductance plateau can be produced by tuning the Fano resonance between QD and the QPC channel. Numerical simulations show results similar to the experiment. A simple model that adds a Fano resonance peak to the QPC's quantized conductance curve is introduced. According to the model, the plateau results when the increase in Fano peak conductance compensates for the decrease in QPC conductance when the QPC gate is pinched off. These results suggest that Fano resonance is a possible candidate for the origin of the 0.7 conductance anomaly observed in QPCs.