Coulomb effects in artificial molecules

TL;DR

This paper investigates Coulomb interactions in artificial molecules made of coupled quantum dots, analyzing how these interactions influence capacitance spectra and tunneling behavior, with implications for understanding quantum dot systems.

Contribution

It introduces an extended Hubbard Hamiltonian model that includes quantum confinement, Coulomb interactions, and tunneling, providing new insights into the spectral and conductance properties of coupled quantum dots.

Findings

Interdot Coulomb interaction dominates in weak coupling regimes.

Correlations significantly affect tunneling probabilities.

Selection rules are crucial for interpreting conductance spectra.

Abstract

We study the capacitance spectra of artificial molecules consisting of two and three coupled quantum dots from an extended Hubbard Hamiltonian model that takes into account quantum confinement, intra- and inter-dot Coulomb interaction and tunneling coupling between all single particle states in nearest neighbor dots. We find that, for weak coupling, the interdot Coulomb interaction dominates the formation of a collective molecular state. We also calculate the effects of correlations on the tunneling probability through the evaluation of the spectral weights, and corroborate the importance of selection rules for understanding experimental conductance spectra.