Spin splitting in open quantum dots and related systems / Martin Evaldsson.
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Evaldsson, Martin, 1977- (författare)
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- Linköpings universitet. Institutionen för teknik och naturvetenskap (utgivare)
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Alternativt namn: Linköping University. Department of Science and Technology
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Alternativt namn: ITN
- Publicerad: Norrköping : Department of Science and Technology, Linköping University, 2005
- Engelska 1 onlineresurs (x, 42 sidor)
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Serie: Linköping studies in science and technology. Licentiate thesis, 0280-7971 ; 1210
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Läs hela texten (Sammanfattning och ramberättelse från Linköping University Electronic Press)
Sammanfattning
Ämnesord
Stäng
- This thesis addresses electron spin phenomena in semi-conductor quantum dots/anti-dots from a computational perspective. In the first paper (paper I) we have studied spin-dependent transport through open quantum dots, i.e., dots strongly coupled to their leads, within the Hubbard model. Results in this model were found consistent with experimental data and suggest that spin-degeneracy is lifted inside the dot - even at zero magnetic field. Similar systems were also studied with electron-electron effects incorporated via Density Functional Theory (DFT) in paper III. Within DFT we found a significant spin-polarisation in the dot at low electron densities. As the electron density increases the spin polarisation in the dot gradually diminishes. These findings are consistent with available experimental observations. Notably, the polarisation is qualitatively different from the one found in the Hubbard model - this indicates that the simplified approach to electronelectron interaction in the Hubbard model might not always be reliable. In paper II we propose a spin-filter device based on resonant backscattering of edge states against a quantum anti-dot embedded in a quantum wire. A magnetic field is applied and the spin up/spin down states are separated through Zeeman splitting. Their respective resonant states may be tuned so that the device can be used to filter either spin in a controlled way.
Ämnesord
- Halvledare (sao)
- Semiconductors (LCSH)
Genre
- Avhandlingar (saogf)
Indexterm och SAB-rubrik
- Uccdb Elektronik
Klassifikation
- 537.5 (DDC)
- Uccdb (kssb/7)
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