Tuning the coherent electron-nuclear interaction in a semiconductor quantum dot
type: CreativeWork
description: An electron hosted in a quantum dot (QD) provides a natural realization of the central spin system, as it interacts with the ∼ 10^5 nuclear spins that compose the quantum dot. Ideally, this system can be used to implement a multi-qubit register formed by collective excitations of the nuclei surrounding the electron, or to probe fundamental many-body physics through engineering of collective states. However, a tuneable interaction between the electron and the nuclear ensemble is required to fully benefit from this system. This work describes the realization of an in situ tuneable coherent exchange interaction between the electron and the nuclear ensemble in a GaAs QD via a non-collinear interaction mediated by an anisotropy of the electron g-factor. The first part of this work develops the infrastructure needed to explore the physics of the electron and nuclear spins in the latter part of the work. This begins with a review of the physics relevant to control of the electron spin hosted in a QD, and the formalism of the interactions between the electron and nuclei. This is followed by protocols to process GaAs heterostructructures into diode devices, allowing a single electron to be deterministically loaded into the QD, as well as the construction of a confocal microscope and associated microwave and laser systems to perform all-optical control of the electron spin in the GaAs QD. Following this, extrinsic strain is explored as a method to introduce a tuneable coherent electro-nuclear interaction in a GaAs QD. Two different strain devices are described, and the applied strain is characterized. The drawbacks of the strain-induced interaction are briefly discussed. The final part of the work describes the coherent electron-nuclear interaction mediated by an electron g-factor anisotropy. This begins with the implementation and optimization of nuclear cooling algorithms, pioneered in InGaAs QDs, in the GaAs QD system, which enables control over the mean-field polarization…
abstract: An electron hosted in a quantum dot (QD) provides a natural realization of the central spin system, as it interacts with the ∼ 10^5 nuclear spins that compose the quantum dot. Ideally, this system can be used to implement a multi-qubit register formed by collective excitations of the nuclei surrounding the electron, or to probe fundamental many-body physics through engineering of collective states. However, a tuneable interaction between the electron and the nuclear ensemble is required to fully benefit from this system. This work describes the realization of an in situ tuneable coherent exchange interaction between the electron and the nuclear ensemble in a GaAs QD via a non-collinear interaction mediated by an anisotropy of the electron g-factor. The first part of this work develops the infrastructure needed to explore the physics of the electron and nuclear spins in the latter part of the work. This begins with a review of the physics relevant to control of the electron spin hosted in a QD, and the formalism of the interactions between the electron and nuclei. This is followed by protocols to process GaAs heterostructructures into diode devices, allowing a single electron to be deterministically loaded into the QD, as well as the construction of a confocal microscope and associated microwave and laser systems to perform all-optical control of the electron spin in the GaAs QD. Following this, extrinsic strain is explored as a method to introduce a tuneable coherent electro-nuclear interaction in a GaAs QD. Two different strain devices are described, and the applied strain is characterized. The drawbacks of the strain-induced interaction are briefly discussed. The final part of the work describes the coherent electron-nuclear interaction mediated by an electron g-factor anisotropy. This begins with the implementation and optimization of nuclear cooling algorithms, pioneered in InGaAs QDs, in the GaAs QD system, which enables control over the mean-field polarization…
author: Shofer, Noah
language: eng
keywords: Central spin system, GaAs, Non-collinear interaction, Nuclear spins, Physics, Quantum, Quantum dot, Spin
license: https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/546f179c-1aef-4ad0-a64e-2164e2df719a/download
license: http://purl.org/NET/rdflicense/allrightsreserved
date published: 2024-06-26
date modified: 2026-07-22T22:24:32Z
provider: Cambridge University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Cambridge

PropertyValue
property ID: DOI
value: 10.17863/CAM.114391