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Reference: Bychkov, Andrey, (2003). Quantum effects in artificial atoms. DPhil. University of Oxford.Citable link to this page:

 

Quantum effects in artificial atoms

Abstract: This thesis contains a theoretical and experimental investigation of semiconductor quantumdots (artificial atoms). The first part presents a numerical study of spin effects inGaAs/AlAs modulation-doped quantum dots containing 0 to 50 electrons. A theoreticalmodel is developed to calculate confinement potentials and ground-state electron densitydistributions using the Kohn-Sham local spin-density approximation. Spin polarization,defined as the difference between the up- and down-spin electron densities, is predicted tooccur spontaneously in symmetric quantum dots and in quantum point contacts in the lowdensityregime as a result of electron exchange interactions. This spontaneous magnetizationcan be controlled by an applied gate voltage, which opens up applications in spintronicsand provides a possible explanation for the non-integer quantization of the quantum pointcontact conductance.The second part describes experimental techniques to investigate photon-exciton couplingin InAs/GaAs self-assembled quantum dots. Two experiments on resonant excitationof a single quantum dot are proposed, whereby the quantum-dot emission is distinguishedfrom resonant pump light by either photon bunching of collected photons with referencephotons, or Michelson interferometry. The feasibility study of the proposed experimentsshows that the photon-exciton coupling efficiency must be dramatically increased by puttingthe quantum dot inside an optical microcavity. Novel types of high-quality, low mode-volumesemiconductor microcavities containing quantum dots are designed, fabricated, andstudied on a newly built setup. We present the first results of photoluminescence studiesof InAs quantum dots inside both GaAs single-defect square-lattice photonic-crystal slabsand GaAs/AlAs micropillars, and InAs artificial molecules formed by vertically coupledstrain-assisted quantum dots. The results indicate the potential of these nanostructures forimplementing resonant transfer of quantum information, developing quantum repeaters andentangled-photon sources, and studying QED effects in the strong-coupling regime.

Type of Award:DPhil Level of Award:Doctoral Awarding Institution: University of Oxford Notes:This thesis was digitised thanks to the generosity of Dr Leonard PolonskyNotes:Some copyrighted material has been removed from the downloadable file. To view the full thesis please contact the ORA team.

Contributors

Bouwmeester, DirkMore by this contributor

RoleSupervisor

 

Dirk BouwmeesterMore by this contributor

RoleSupervisor

 Bibliographic Details

Issue Date: 2003Identifiers

Urn: uuid:93a68cff-9823-47d7-9505-b63806f1bbd4

Source identifier: 603826962 Item Description

Type: Thesis;

Language: eng Subjects: Quantum dots Gallium arsenide semiconductors Research Tiny URL: td:603826962

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Autor: Bychkov, Andrey - institutionUniversity of Oxford facultyMathematical and Physical Sciences Division - - - - Contributors Bouwmee

Fuente: https://ora.ox.ac.uk/objects/uuid:93a68cff-9823-47d7-9505-b63806f1bbd4



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