Multiple quantum phases in artificial double-dot molecules

TL;DR

This paper theoretically investigates coupled semiconductor quantum dots, revealing multiple quantum phases and a new phase at intermediate inter-dot distances, which could be observed experimentally.

Contribution

It introduces a generalized Hubbard model for double quantum dots, predicting novel quantum phases and transitions based on realistic electron wavefunctions.

Findings

Identification of multiple quantum phases in double dots

Prediction of a new phase at intermediate inter-dot distance

Observable effects in addition spectra and magnetization

Abstract

We study coupled semiconductor quantum dots theoretically through a generalized Hubbard approach, where intra- and inter-dot Coulomb Correlation, as well as tunneling effects are described on the basis of realistic electron wavefunctions. We find that the ground-state configuration of vertically-coupled double dots undergoes non-trivial quantum transitions as a function of the inter-dot distance d; at intermediate values of d we predict a new phase that should be observable in the addition spectra and in the magnetization changes.