Spin dynamics in semiconductor heterostructures
Spin dynamics in semiconductor heterostructures
This thesis presents experimental investigations of the electron spin dynamics (i.e. the spin relaxation rate, This thesis presents experimental investigations of the electron spin dynamics(i.e. the spin relaxation rate, Γs, and the g-factor, g * ) inGaAs/ AlGaAs based semiconductor heterostructures and the effect of symmetry breaking perturbations such as; an applied external electric field, shear strain or graded alloy composition in the barriers. Spin-polarised electron populations are generated and detected using optical methods.
Quantum wells grown on a (001) zinc-blende substrate display isotropic inplane spin dynamics. The above perturbations act to lower the symmetry and therefore the spin dynamics are allowed to show in plane anisotropy. However, the microscopic origin of the anisotropy of Γs is different to that of g* . This thesis contains a full study of the anisotropy of both Γs and g* for all of the above perturbations. This reveals the microscopic effects on the band edges of the perturbations.It has previously been shown theoretically that strain applied in the plane of (110) or (111) oriented quantum wells can act to cancel the spin-orbit field from bulk inversion asymmetry. In this thesis, we study the effect on the spin dynamics of strain applied to a (110) quantum well and also investigate a (111) sample for its suitability in such experiments.
English, David
efe79c85-c716-4d97-9092-060a72069efb
April 2012
English, David
efe79c85-c716-4d97-9092-060a72069efb
Harley, R.T.
54613031-f60f-45f4-9b20-e49bcfd53b77
English, David
(2012)
Spin dynamics in semiconductor heterostructures.
University of Southampton, Faculty of Physical and Applied Sciences, Doctoral Thesis, 121pp.
Record type:
Thesis
(Doctoral)
Abstract
This thesis presents experimental investigations of the electron spin dynamics (i.e. the spin relaxation rate, This thesis presents experimental investigations of the electron spin dynamics(i.e. the spin relaxation rate, Γs, and the g-factor, g * ) inGaAs/ AlGaAs based semiconductor heterostructures and the effect of symmetry breaking perturbations such as; an applied external electric field, shear strain or graded alloy composition in the barriers. Spin-polarised electron populations are generated and detected using optical methods.
Quantum wells grown on a (001) zinc-blende substrate display isotropic inplane spin dynamics. The above perturbations act to lower the symmetry and therefore the spin dynamics are allowed to show in plane anisotropy. However, the microscopic origin of the anisotropy of Γs is different to that of g* . This thesis contains a full study of the anisotropy of both Γs and g* for all of the above perturbations. This reveals the microscopic effects on the band edges of the perturbations.It has previously been shown theoretically that strain applied in the plane of (110) or (111) oriented quantum wells can act to cancel the spin-orbit field from bulk inversion asymmetry. In this thesis, we study the effect on the spin dynamics of strain applied to a (110) quantum well and also investigate a (111) sample for its suitability in such experiments.
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Published date: April 2012
Organisations:
University of Southampton, Quantum, Light & Matter Group
Identifiers
Local EPrints ID: 340899
URI: http://eprints.soton.ac.uk/id/eprint/340899
PURE UUID: 5f00a184-4eae-48a9-acf0-ad3b4a0f059c
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Date deposited: 01 Jul 2013 14:31
Last modified: 14 Mar 2024 11:31
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Contributors
Author:
David English
Thesis advisor:
R.T. Harley
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