Singlet-triplet spin blockade and charge sensing in a few-electron double quantum dot

TL;DR

This paper investigates singlet-triplet spin blockade in a few-electron double quantum dot, demonstrating charge transport suppression, the influence of magnetic field on exchange splitting, and developing a model that aligns well with experimental data.

Contribution

It introduces a simple model for current and charge distribution in spin-blockade conditions, validated by experimental results.

Findings

Transport from (1,1) to (0,2) states is suppressed.

Spin blockade is lifted at high bias when triplet states enter the transport window.

The model accurately predicts charge and current behavior under spin-blockade conditions.

Abstract

Singlet-triplet spin blockade in a few-electron lateral double quantum dot is investigated using simultaneous transport and charge-sensing measurements. Transport from the (1,1) to the (0,2) electron occupancy states is strongly suppressed relative to the opposite bias [(0,2) to (1,1)]. At large bias, spin blockade ceases as the (0,2) triplet state enters the transport window, giving a direct measure of exchange splitting as a function of magnetic field. A simple model for current and steady-state charge distribution in spin-blockade conditions is developed and found to be in excellent agreement with experiment.