Filling a gap in the literature, this up-to-date introduction to the field provides an overview of current experimental techniques, basic theoretical concepts, and sample fabrication methods. Following an introduction, this monograph deals with optically active quantum dots and their integration into electro-optical devices, before looking at the theory of quantum confined states and quantum dots interacting with the radiation field. Final chapters cover spin-spin interaction in quantum dots as well as spin and charge states, showing how to use single spins for break-through quantum computation. A conclusion and outlook round off the volume. The result is a primer providing the essential basic knowledge necessary for young researchers entering the field, as well as semiconductor and theoretical physicists, PhD students in physics and material sciences, electrical engineers and materials scientists.
Author(s): Oliver Gywat, Hubert J. Krenner, Jesse Berezovsky
Publisher: Wiley-VCH
Year: 2010
Language: English
Pages: 221
Tags: Физика;Физика твердого тела;Магнитные свойства твердых тел;
Spins in Optically Active Quantum Dots......Page 5
Contents......Page 7
Preface......Page 11
1 Introduction......Page 13
1.1 Spin......Page 14
1.2 Spin-1/2 Basics......Page 15
1.3 Quantum Dots......Page 19
1.3.1 Spin-Based Quantum Information Processing with Artificial Atoms......Page 20
1.3.3 “Natural” Quantum Dots......Page 23
2.1 Epitaxial Quantum Dots......Page 27
2.2.1 Structure and Fabrication......Page 30
2.2.2 Energy Levels and Optical Transitions......Page 31
2.3 Self-Assembled Quantum Dots......Page 33
2.3.1 Strain-Driven Self-Alignment......Page 34
2.3.2 Optical Properties and QD Shell Structure......Page 36
2.4.1 Electrically Gated Quantum Dots......Page 39
2.4.2 Advanced MBE Techniques......Page 41
2.4.3 Nanowire Quantum Dots......Page 43
2.5 Chemically-Synthesized Quantum Dots......Page 44
2.5.1 Colloidal Growth......Page 45
2.5.2 Energy Level Structure and Optical Properties......Page 46
3.1 Band Structure of III–V Semiconductors......Page 51
3.1.1 Effective Mass of Crystal Electrons......Page 52
3.1.3 Band Structure Close to the Band Edges......Page 53
3.1.4 Band-Edge Bloch States......Page 54
3.1.5 Coupling of Bands and the Luttinger Hamiltonian......Page 55
3.1.6 Splitting of Heavy Hole and Light Hole Bands......Page 58
3.2 Quantum Confinement......Page 59
3.2.2 Quantum Dot Confinement......Page 60
3.3 Spherical Quantum Dot Confinement......Page 61
3.3.1 Conduction-Band States......Page 62
3.3.2 Valence Band States......Page 65
3.4 Parabolic Quantum Dot Confinement......Page 67
3.5.1 Symmetry of Many-Particle States in Quantum Dots......Page 69
3.5.2 Coulomb Interaction......Page 70
3.5.3 The Concept of Excitons in Quantum Dots......Page 71
3.5.4 Carrier Configurations in the s Shell and Energies......Page 72
3.6.1 From Ensemble to Single Quantum Dot Spectra......Page 73
3.6.2 Transition Energies of Few-Particle States......Page 75
4.1.1 Semiconductor Diodes......Page 79
4.1.2 Voltage-Controlled Number of Charges......Page 81
4.1.3 Optically Probing Coulomb Blockade......Page 83
4.1.4 Quantum Confined Stark Effect......Page 85
4.2 Optical Cavities......Page 89
5.1.1 Electromagnetic Field......Page 95
5.1.2 Nonrelativistic Electron–Photon Interaction......Page 96
5.1.3 Total Hamiltonian for a Quantum Dot and a Field......Page 97
5.2 Electric Dipole Transitions......Page 98
5.2.1 Electric Dipole Selection Rules......Page 100
5.2.2 Interband Transitions in a III–V Semiconductor......Page 101
5.2.3 Equivalent Classical Electric Dipole Picture......Page 103
5.2.4 Semiclassical Interaction with a Laser Field......Page 104
5.4 Generalized Master Equation of the Driven Two-Level System......Page 105
5.4.2 System-Reservoir Approach......Page 106
5.5 Cavity Quantum Electrodynamics......Page 109
5.5.1 Strong Coupling Regime......Page 110
5.5.2 Weak Coupling Regime......Page 111
5.6.1 Lamb Shift and AC Stark Shift......Page 112
5.6.2 Two Emitters Interacting with a Cavity......Page 114
6.1 Electron–Electron–Spin Interaction......Page 115
6.2 Electron–Hole Exchange Interaction......Page 116
6.2.1 Exciton Fine Structure......Page 117
6.2.2 Biexcitons and Polarization-Entangled Photons......Page 119
6.3 Hyperfine Interaction......Page 121
7 Experimental Methods for Optical Initialization, Readout, and Manipulation of Spins......Page 123
7.1 Optical Spin Initialization......Page 124
7.1.1 Nonresonant Spin Pumping......Page 126
7.1.2 Resonant Spin Pumping......Page 129
7.1.3 Nuclear Spin Pumping......Page 132
7.2 Optical Spin Readout......Page 135
7.2.1 Time-Resolved Photoluminescence......Page 136
7.2.2 Spin Storage and Retrieval......Page 137
7.2.3 Magnetic Ions......Page 142
7.2.4 Spin-Selective Absorption......Page 144
7.3.1 The Hanle Effect......Page 146
7.3.2 Ensemble Hanle Effect......Page 147
7.3.3 Hanle Effect Measurement of a Single Quantum Dot......Page 149
7.3.4 Time-Resolved Faraday Rotation Spectroscopy......Page 152
7.3.5 Coherent Spin Echos – Measurement of T2......Page 157
7.3.6 Single Spin Kerr Rotation Measurement......Page 160
7.3.7 Time-Resolved Observation of Single Spin Coherence......Page 165
7.3.8 Optical Spin Manipulation......Page 169
7.3.9 Putting It All Together......Page 175
8.1.1 A Toy Model for Coupled Systems: The Two-Site Hubbard Model......Page 179
8.1.2 An Exciton in a QD Molecule: A Coupled System......Page 182
8.2 Molecular Theory of Confined States in Coupled Quantum Dots......Page 185
8.3.1 Optical Response with Initial and Final State Couplings......Page 186
8.3.2 Electric Field Induced Coupling of Charged Trions in a QD Molecule......Page 189
8.4 Future Directions......Page 192
Appendix A Valence Band States for Spherical Confinement......Page 195
Appendix B List of Constants......Page 199
Appendix C Material Parameters......Page 201
References......Page 203
Index......Page 219
