Unconventional Transport in the "Hole" Regime of a Si Double Quantum Dot

TL;DR

This paper reveals that traditional models fail to explain charge transport in a silicon double quantum dot's three-electron regime, and introduces a new spin-flip cotunneling process that overcomes a singlet blockade.

Contribution

The study uncovers a novel spin-flip cotunneling mechanism in silicon double quantum dots, challenging conventional charge transport models in the three-electron regime.

Findings

Conventional models cannot fully explain experimental data.

Identification of a new spin-flip cotunneling process.

This process lifts the singlet blockade in the system.

Abstract

Studies of electronic charge transport through semiconductor double quantum dots rely on a conventional "hole" model of transport in the three-electron regime. We show that experimental measurements of charge transport through a Si double quantum dot in this regime cannot be fully explained using the conventional picture. Using a Hartree-Fock (HF) formalism and relevant HF energy parameters extracted from transport data in the multiple-electron regime, we identify a novel spin-flip cotunneling process that lifts a singlet blockade.