
Proceedings Paper
Modeling optically pumped NMR and spin polarization in GaAs/AlGaAs quantum wellsFormat | Member Price | Non-Member Price |
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Paper Abstract
Optically-pumped nuclear magnetic resonance (OPNMR) spectroscopy is an emerging technique to probe electronic
and nuclear spin properties in bulk and quantum well semiconductors. In OPNMR, one uses optical
pumping with light to create spin-polarized electrons in a semiconductor. The electron spin can be transferred
to the nuclear spin bath through the Fermi contact hyperfine interaction which can then be detected by conventional
NMR. The resulting NMR signal can be enhanced four to five orders of magnitude or more over the
thermal equilibrium signal. In previous work, we studied OPNMR in bulk GaAs where we investigated the
strength of the OPNMR signal as a function of the pump laser frequency. This allowed us to study the spin-split
valence band. Here we report on OPNMR studies in GaAs/AlGaAs quantum wells. We focus on theoretical
calculations for the average electron spin polarization at different photon energies for different values of external
magnetic field in both unstrained and strained quantum wells. Our calculations allow us to identify the Landau
level transitions which are responsible for the peaks in the photon energy dependence of the OPNMR signal
intensity. The calculations are based on the 8- band Pidgeon-Brown model generalized to include the effects
of the quantum confinement potential as well as pseudomorphic strain at the interfaces. Optical properties are
calculated within the golden rule approximation. Detailed comparison to experiment allows one to accurately
determine valence band spin splitting in the quantum wells including the effects of strain.
Paper Details
Date Published: 28 August 2014
PDF: 8 pages
Proc. SPIE 9167, Spintronics VII, 91670N (28 August 2014); doi: 10.1117/12.2061101
Published in SPIE Proceedings Vol. 9167:
Spintronics VII
Henri-Jean Drouhin; Jean-Eric Wegrowe; Manijeh Razeghi, Editor(s)
PDF: 8 pages
Proc. SPIE 9167, Spintronics VII, 91670N (28 August 2014); doi: 10.1117/12.2061101
Show Author Affiliations
D. Saha, Univ. of Florida (United States)
R. Wood, Univ. of Florida (United States)
J. T. Tokarski III, Univ. of Florida (United States)
L. A. McCarthy, Univ. of Florida (United States)
C. R. Bowers, Univ. of Florida (United States)
E. L. Sesti, Washington Univ. in St. Louis (United States)
R. Wood, Univ. of Florida (United States)
J. T. Tokarski III, Univ. of Florida (United States)
L. A. McCarthy, Univ. of Florida (United States)
C. R. Bowers, Univ. of Florida (United States)
E. L. Sesti, Washington Univ. in St. Louis (United States)
S. E. Hayes, Washington Univ. in St. Louis (United States)
P. L. Kuhns, National High Magnetic Field Lab. (United States)
S. A. McGill, National High Magnetic Field Lab. (United States)
A. R. Reyes, National High Magnetic Field Lab. (United States)
G. D. Sanders, Univ. of Florida (United States)
C. J. Stanton, Univ. of Florida (United States)
P. L. Kuhns, National High Magnetic Field Lab. (United States)
S. A. McGill, National High Magnetic Field Lab. (United States)
A. R. Reyes, National High Magnetic Field Lab. (United States)
G. D. Sanders, Univ. of Florida (United States)
C. J. Stanton, Univ. of Florida (United States)
Published in SPIE Proceedings Vol. 9167:
Spintronics VII
Henri-Jean Drouhin; Jean-Eric Wegrowe; Manijeh Razeghi, Editor(s)
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