Fano Effect in a Few-Electron Quantum Dot

TL;DR

This paper investigates the Fano effect in a few-electron quantum dot coupled to a quantum wire, revealing interference phenomena, electron charging effects, and shell structure, with implications for quantum dot electron confinement.

Contribution

It demonstrates the Fano effect in a quantum dot-wire system and explains the rapid Fano parameter sign inversion through finite coupling width.

Findings

Observation of conductance modification due to Fano interference

Identification of shell structure in the addition energy spectrum

Sign inversion of the Fano parameter explained by coupling width

Abstract

We have studied the Fano effect in a few-electron quantum dot side-coupled to a quantum wire. The conductance of the wire, which shows an ordinal staircase-like quantization without the dot, is modified through the interference (the Fano effect) and the charging effects. These effects are utilized to verify the exhaustion of electrons in the dot. The "addition energy spectrum" of the dot shows a shell structure, indicating that the electron confinement potential is fairly circular. A rapid sign inversion of the Fano parameter on the first conductance plateau with the change of the wire gate voltage has been observed, and explained by introducing a finite width of dot-wire coupling.