Selection Rules for Transport Excitation Spectroscopy of Few-Electron Quantum Dots

TL;DR

This paper investigates how electron correlations in few-electron quantum dots influence transport spectroscopy, revealing that Coulomb interactions suppress many tunneling processes except those involving center-of-mass excitations, which dominate the spectra.

Contribution

It provides theoretical calculations showing the selective suppression of tunneling channels due to Coulomb correlations in quantum dots.

Findings

Coulomb interactions strongly suppress most excited state tunneling processes.

Center-of-mass mode excitations are unaffected by Coulomb interactions.

Transport spectra are dominated by channels involving center-of-mass excitations.

Abstract

Tunneling of electrons traversing a few-electron quantum dot is strongly influenced by the Coulomb interaction leading to Coulomb blockade effects and single-electron tunneling. We present calculations which demonstrate that correlations between the electrons cause a strong suppression of most of the energetically allowed tunneling processes involving excited dot states. The excitation of center-of-mass modes, in contrast, is unaffected by the Coulomb interaction. Therefore, channels connected to these modes dominate the excitation spectra in transport measurements.