Detection of spin polarization utilizing singlet and triplet states in a single-lead quantum dot

TL;DR

This paper introduces a novel method to detect local spin polarization in semiconductor micro devices at low magnetic fields by monitoring singlet and triplet states in a single-lead quantum dot, revealing local spin phenomena undetectable by traditional methods.

Contribution

The paper presents a new detection scheme for local spin polarization using a single-lead quantum dot, validated with quantum Hall edge states, and capable of revealing subtle spin features.

Findings

Detection of local spin polarization at low magnetic fields.

Validation of the method with quantum Hall edge states.

Observation of non-zero spin polarization at device edges.

Abstract

We propose and demonstrate a new method to probe local spin polarization in semiconductor micro devices at low and zero magnetic fields. By connecting a single-lead quantum dot to a semiconductor micro device and monitoring electron tunneling into singlet and triplet states in the dot, we can detect the local spin polarization formed in the target device. We confirm the validity of this detection scheme utilizing spin split quantum Hall edge states. We also observe non-zero local spin polarization at the device edge in low magnetic fields, which is not detectable with conventional macroscopic probes.