Details
| Original language | English |
|---|---|
| Article number | 165305 |
| Journal | Physical Review B - Condensed Matter and Materials Physics |
| Volume | 71 |
| Issue number | 16 |
| Publication status | Published - 7 Apr 2005 |
Abstract
We present a detailed experimental and theoretical analysis of the optical orientation of electron spins in GaAs/AlAs quantum wells. Using time and polarization resolved photoluminescence excitation spectroscopy, the initial degree of electron-spin polarization is measured as a function of excitation energy for a sequence of quantum wells with well widths between 63 and 198 Å. The experimental results are compared with an accurate theory of excitonic absorption taking fully into account electron-hole Coulomb correlations and heavy-hole-light-hole coupling. We find in wide quantum wells that the measured initial degree of polarization of the luminescence follows closely the spin polarization of the optically excited electrons calculated as a function of energy. This implies that the orientation of the electron spins is essentially preserved when the electrons relax from the optically excited high-energy states to quasithermal equilibrium of their momenta. Due to initial spin relaxation, the measured polarization in narrow quantum wells is reduced by a constant factor that does not depend on the excitation energy.
ASJC Scopus subject areas
- Materials Science(all)
- Electronic, Optical and Magnetic Materials
- Physics and Astronomy(all)
- Condensed Matter Physics
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In: Physical Review B - Condensed Matter and Materials Physics, Vol. 71, No. 16, 165305, 07.04.2005.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Optical orientation of electron spins in GaAs quantum wells
AU - Pfalz, Stefan
AU - Winkler, Roland
AU - Nowitzki, Tobias
AU - Reuter, Dirk
AU - Wieck, Andreas D.
AU - Hägele, Daniel
AU - Oestreich, Michael
PY - 2005/4/7
Y1 - 2005/4/7
N2 - We present a detailed experimental and theoretical analysis of the optical orientation of electron spins in GaAs/AlAs quantum wells. Using time and polarization resolved photoluminescence excitation spectroscopy, the initial degree of electron-spin polarization is measured as a function of excitation energy for a sequence of quantum wells with well widths between 63 and 198 Å. The experimental results are compared with an accurate theory of excitonic absorption taking fully into account electron-hole Coulomb correlations and heavy-hole-light-hole coupling. We find in wide quantum wells that the measured initial degree of polarization of the luminescence follows closely the spin polarization of the optically excited electrons calculated as a function of energy. This implies that the orientation of the electron spins is essentially preserved when the electrons relax from the optically excited high-energy states to quasithermal equilibrium of their momenta. Due to initial spin relaxation, the measured polarization in narrow quantum wells is reduced by a constant factor that does not depend on the excitation energy.
AB - We present a detailed experimental and theoretical analysis of the optical orientation of electron spins in GaAs/AlAs quantum wells. Using time and polarization resolved photoluminescence excitation spectroscopy, the initial degree of electron-spin polarization is measured as a function of excitation energy for a sequence of quantum wells with well widths between 63 and 198 Å. The experimental results are compared with an accurate theory of excitonic absorption taking fully into account electron-hole Coulomb correlations and heavy-hole-light-hole coupling. We find in wide quantum wells that the measured initial degree of polarization of the luminescence follows closely the spin polarization of the optically excited electrons calculated as a function of energy. This implies that the orientation of the electron spins is essentially preserved when the electrons relax from the optically excited high-energy states to quasithermal equilibrium of their momenta. Due to initial spin relaxation, the measured polarization in narrow quantum wells is reduced by a constant factor that does not depend on the excitation energy.
UR - http://www.scopus.com/inward/record.url?scp=28644442513&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.71.165305
DO - 10.1103/PhysRevB.71.165305
M3 - Article
AN - SCOPUS:28644442513
VL - 71
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
SN - 1098-0121
IS - 16
M1 - 165305
ER -