Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Confinement sensitivity in quantum dot singlet-triplet relaxation
Stockholm University, Faculty of Science, Department of Physics.
Stockholm University, Faculty of Science, Department of Physics.
(English)Manuscript (preprint) (Other academic)
National Category
Physical Sciences Nano Technology
Research subject
Physics
Identifiers
URN: urn:nbn:se:su:diva-142132OAI: oai:DiVA.org:su-142132DiVA: diva2:1091181
Available from: 2017-04-26 Created: 2017-04-26 Last updated: 2017-04-28Bibliographically approved
In thesis
1. Confinement Sensitivity in Quantum Dot Spin Relaxation
Open this publication in new window or tab >>Confinement Sensitivity in Quantum Dot Spin Relaxation
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Quantum dots, also known as artificial atoms, are created by tightly confining electrons, and thereby quantizing their energies. They are important components in the emerging fields of nanotechnology where their potential uses vary from dyes to quantum computing qubits. Interesting properties to investigate are e.g. the existence of atom-like shell structures and lifetimes of prepared states.

Stability and controllability are important properties in finding applications to quantum dots. The ability to prepare a state and change it in a controlled manner without it loosing coherence is very useful, and in some semiconductor quantum dots, lifetimes of up to several milliseconds have been realized. Here we focus on dots in semiconductor materials and investigate how the confined electrons are effected by their experienced potential.

The shape of the dot will effect its properties, and is important when considering a suitable model. Structures elongated in one dimension, often called nanowires, or shaped as rings have more one-dimensional characteristics than completely round or square dots. The two-dimensional dots investigated here are usually modeled as harmonic oscillators, however we will also consider circular well models.

The effective potential confining the electrons is investigated both in regard to how elliptical it is, as well as how results differ when using a harmonic oscillator or a circular well potential. By mixing spin states through spin-orbit interaction transitioning between singlet and triplet states becomes possible with spin independent processes such as phonon relaxation. We solve the spin-mixing two-electron problem numerically for some confinement, and calculate the phonon transition rate between the lowest energy singlet and triplet states using Fermi's golden rule.

The strength of the spin-orbit interaction is varied both by changing the coupling constants, and by applying an external, tilted, magnetic field. The relation between magnetic field parameters and dot parameters are used to maximize state lifetimes, and to model experimental results.

Place, publisher, year, edition, pages
Stockholm: Department of Physics, Stockholm University, 2017. 64 p.
National Category
Nano Technology Other Physics Topics Atom and Molecular Physics and Optics
Research subject
Physics
Identifiers
urn:nbn:se:su:diva-142133 (URN)978-91-7649-809-5 (ISBN)978-91-7649-810-1 (ISBN)
Public defence
2017-06-08, sal FB55, AlbaNova universitetscentrum, Roslagstullsbacken 21, Stockholm, 13:15 (English)
Opponent
Supervisors
Note

At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 3: Manuscript.

Available from: 2017-05-16 Created: 2017-04-26 Last updated: 2017-05-16Bibliographically approved

Open Access in DiVA

No full text

Search in DiVA

By author/editor
Wesslén, Carl-JohanLindroth, Eva
By organisation
Department of Physics
Physical SciencesNano Technology

Search outside of DiVA

GoogleGoogle Scholar

Total: 30 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf