Charge-localization and isospin-blockade in vertical double quantum dots

TL;DR

This paper investigates charge localization and isospin blockade phenomena in vertical double quantum dots, revealing strong localization effects and ground state transitions driven by magnetic fields and Coulomb interactions.

Contribution

It uncovers charge localization in three-electron double quantum dots linked to magnetic field-induced ground state transitions and isospin blockade signatures.

Findings

Charge localization occurs at specific magnetic fields.

Ground state transitions involve parity changes.

Strong isospin blockade signatures are observed in transport.

Abstract

Charge localization seems unlikely to occur in two vertically coupled symmetric quantum dots even if a small bias voltage breaks the exact isospin-symmetry of the system. However for a three-electron double quantum dot we find a strong localization of charges at certain vertically applied magnetic fields. The charge localization is directly connected to new ground state transitions between eigenstates differing only in parity. The transitions are driven by magnetic field dependent Coulomb correlations between the electrons and give rise to strong isospin blockade signatures in transport through the double dot system.