Spin-Related Current Suppression in a Semiconductor-Quantum-Dot Spin-Diode Structure

TL;DR

This study investigates how spin blockade effects suppress electron current in a semiconductor quantum dot spin-diode structure with asymmetric lead coupling, revealing anomalous current suppression linked to spin interactions.

Contribution

The paper presents experimental evidence of spin-related current suppression in a quantum dot spin-diode, highlighting the role of spin blockade at the QD/FM interface.

Findings

Asymmetric Coulomb diamonds observed in transport measurements.

Anomalous current suppression during two-electron tunneling.

Spin blockade mechanisms likely cause the observed suppression.

Abstract

We experimentally study the transport features of electrons in a spin-diode structure consisting of a single semiconductor quantum dot (QD) weakly coupled to one nonmagnetic (NM) and one ferromagnetic (FM) lead, in which the QD has an artificial atomic nature. A Coulomb stability diamond shows asymmetric features with respect to the polarity of the bias voltage. For the regime of two-electron tunneling, we find anomalous suppression of the current for both forward and reverse bias. We discuss possible mechanisms of the anomalous current suppression in terms of spin blockade via the QD/FM interface at the ground state of a two-electron QD.