P-shell carriers assisted dynamic nuclear spin polarization in single quantum dots at zero external magnetic field

Repeated injection of spin polarized carriers in a quantum dot leads to the polarization of nuclear spins, a process known as dynamic nuclear spin polarization (DNP). Here, we report the first observation of p-shell carrier assisted DNP in single QDs at zero external magnetic field. The nuclear fiel...

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Bibliographic Details
Published in:arXiv.org 2016-01
Main Authors: Fong, C F, Ota, Y, Harbord, E, Iwamoto, S, Arakawa, Y
Format: Article
Language:English
Subjects:
Computer simulation
Electron spin
Electrons
Excitons
Magnetic fields
Mathematical models
Nuclear spin
Polarization (spin alignment)
Quantum dots
Spin dynamics
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Summary:Repeated injection of spin polarized carriers in a quantum dot leads to the polarization of nuclear spins, a process known as dynamic nuclear spin polarization (DNP). Here, we report the first observation of p-shell carrier assisted DNP in single QDs at zero external magnetic field. The nuclear field - measured by using the Overhauser shift of the singly charged exciton state of the QDs - continues to increase, even after the carrier population in the s-shell saturates. This is also accompanied by an abrupt increase in nuclear spin buildup time as p-shell emission overtakes that of the s-shell. We attribute the observation to p-shell electrons strongly altering the nuclear spin dynamics in the QD, supported by numerical simulation results based on a rate equation model of coupling between electron and nuclear spin system. DNP with p-shell carriers could open up avenues for further control to increase the degree of nuclear spin polarization in QDs.
ISSN:2331-8422
DOI:10.48550/arxiv.1601.03480