Tunneling and Electric-Field Effects on Electron-Hole Localization in Artificial Molecules

TL;DR

This paper theoretically explores how tunneling and electric fields influence electron-hole localization in coupled quantum dots, revealing enhanced tunability of optical properties relevant for quantum information applications.

Contribution

It provides a detailed theoretical analysis of the Stark effect in coupled quantum dots, highlighting the interplay of tunneling, electric field, and interactions for quantum computing.

Findings

Coupling enhances optical property tunability.

Optimal coupling balances tunneling, field, and interactions.

Potential for exciton-based qubits in coupled dots.

Abstract

We theoretically investigate the Stark shift of the exciton goundstate in two vertically coupled quantum dots as a function of the interdot distance. The coupling is shown to enhance the tuneability of the linear optical properties, including energy and oscillator strength, as well as the exciton polarizability. The coupling regime that maximizes these properties results from the detailed balance between the effects of the single-particle tunneling, of the electric field and of the carrier-carrier interaction. We discuss the relevance of these results to the possible implementation of quantum-information processing based on semiconductor quantum dots: in particular, we suggest the identification of the qubits with the exciton levels in coupled- rather than single-dots.