Coherent Magnetotransport Through an Artificial Molecule

TL;DR

This paper predicts that magnetic fields can suppress certain conductance peaks and enhance localization in quantum dot arrays, revealing coherent molecular states and giant magnetoconductance effects due to many-body interactions.

Contribution

It introduces a detailed Hubbard model analysis of quantum dot arrays, highlighting magnetic field effects on conductance and localization, and predicts new signatures of coherence and giant magnetoconductance.

Findings

Suppression of resonant conductance peaks under magnetic field

Density-dependent spin-polarization transition as a coherence signature

Giant magnetoconductance due to many-body localization enhancement

Abstract

The conductance in an extended multiband Hubbard model describing linear arrays of up to ten quantum dots is calculated via a Lanczos technique. A pronounced suppression of certain resonant conductance peaks in an applied magnetic field due to a density-dependent spin-polarization transition is predicted to be a clear signature of a coherent ``molecular'' wavefunction in the array. A many-body enhancement of localization is predicted to give rise to a {\em giant magnetoconductance} effect in systems with magnetic scattering.