Coexistence of parallel and series current paths in parallel-coupled double quantum dots in nonlinear transport regime

TL;DR

This study explores how magnetic fields influence electron transport in double quantum dots, revealing coexistence of parallel and series conduction paths due to magnetic-field-induced tunnel-coupling changes.

Contribution

It demonstrates the coexistence of parallel and series current paths in double quantum dots under magnetic fields, highlighting the role of magnetic-field-induced tunnel-coupling modifications.

Findings

Electron tunneling observed at low magnetic fields.

Coexistence of parallel and series conduction at high magnetic fields.

Pauli spin blockade indicating series tunneling.

Abstract

We investigated the electron transport properties of parallel-coupled double quantum dot (DQD) devices under magnetic fields. When a low magnetic field was applied, electron tunneling through parallel-coupled DQDs was observed. Under a high magnetic field, we observed both electron tunneling through parallel- and series-coupled DQDs under nonlinear transport conditions. In addition, the Pauli spin blockade was observed, indicating tunneling through the series-coupled DQDs. We attribute these behaviors to the magnetic-field-induced changes in the tunnel-couplings that allow the coexistence of the current paths of the parallel and series configurations.