Electron Spin Resonance and Related Phenomena in Low-Dimensional Structures (eBook)

Marco Fanciulli is the Director of the CNR-INFM MDM (Materials and Devices for Microelectronics) National Laboratory and Full Professor at the Department of Material Science at the University of Milano Bicocca.

Foreword 6
Index 7
Preface 8
Contents 10
Resistively Detected ESR and ENDOR Experiments in Narrow and Wide Quantum Wells: A Comparative Study 16
Introduction 16
Theory 17
Experiment 19
Results 19
Conclusions 26
Acknowledgements 27
References 27
Index 28
Electron-Spin Manipulation in Quantum Dot Systems 29
Introduction 29
Single-Spin Manipulation 30
Oscillating Magnetic Field 31
Slanting Zeeman Field 33
Two-Spin Interaction 37
Formulation 37
Hybrid Double Dots 41
Double QD with Slanting Zeeman Field 44
Conclusion 45
Acknowledgments 45
References 45
Index 48
Resistively Detected NMR in GaAs/AlGaAs 49
Nuclear Magnetic Resonances with `Too Few Spins' 50
The `Too Few Spins' Problem 50
The Conventional NMR of Bloch and Purcell 50
NMR for Nanostructured Materials 51
Electrons as an In-Situ Detector of the NMR 51
Electrical Detection of the NMR in GaAs/AlGaAs in 1988 51
The Strong Overhauser Field of GaAs/AlGaAs 52
Nuclear-Spin-Dependent Transport in the Quantum Hall Regime 53
Recent Advances in GaAs/AlGaAs Semiconductor Quantum Wells 54
Resistively Detected NMR Lineshapes in GaAs/AlGaAs 54
Resistive NMR Lineshapes 54
Skyrmions in the Ground State of Quantum Hall 56
Spin-Lattice Relaxation-Time Measurements 57
T1 and the Evidence for a Skyrmion Crystal 58
T1 in the Electron Solid Phases of GaAs/AlGaAs 59
Towards a Complete NMR Probe of Quantum Structures 60
NMR in Quantum Electronic Structures of GaAs/AlGaAs 60
NMR on a Chip: Quantum Coherent Control of the Nuclear Spins at the Nanoscale 61
Concluding Remarks 62
Acknowledgements 62
References 62
Index 63
Electron-Spin Dynamics in Self-Assembled (In,Ga)As/GaAs Quantum Dots 65
Introduction 65
Experiment 67
Electron g-Factor 68
Creation of Spin Coherence by Spin Initialization 70
Electron-Spin Coherence 79
Summary 91
Acknowledgements 92
References 92
Index 94
Single-Electron-Spin Measurements in Si-Based Semiconductor Nanostructures 95
Introduction 95
Measurements of a Single Spin in the SiO2 of a Submicrometer Si Field Effect Transistor 97
Statistical Measurements 98
Detection of Electron-Spin Resonance (ESR) of a Single Spin 102
Single-Shot Measurement 105
Fabrication and Characterization of Electrostatically Confined Quantum-Dot Structures in Si/SiGe Heterostructures 105
Demonstration of a One-Electron Quantum Dot 106
Characterization of the Spin-Transition Sequence 109
Single-Shot Measurement 110
Concluding Remarks 112
Acknowledgements 112
References 112
Index 114
Si/SiGe Quantum Devices, Quantum Wells, and Electron-Spin Coherence 115
Introduction 116
Silicon Quantum Devices 117
Spins and Valleys 120
ESR in Silicon Quantum Wells 121
Samples 123
ESR Measurements 124
Decoherence Analysis 125
Results 127
Conclusions 129
Acknowledgments 129
References 129
Index 140
Electrical Detection of Electron-Spin Resonance in Two-Dimensional Systems 142
Mechanism of Electrical Detection 142
Determination of Spin-Relaxation Times 146
References 151
Index 153
Quantitative Treatment of Decoherence 154
Introduction 154
Measures of Decoherence 155
Relaxation Timescales 155
Quantum Entropy 156
Fidelity 156
Norm of Deviation 158
Arbitrary Initial States 158
Decoherence of Double Quantum-Dot Charge Qubits 159
Model 160
Piezoelectric Interaction 161
Deformation Interaction 163
Error Estimates During Gate Functions 164
Relaxation During the NOT Gate 164
Dephasing During a Phase Gate 167
Qubit Error Estimates 168
Additivity of Decoherence Measures 170
The Maximal Deviation Norm 171
Upper Bound for Measure of Decoherence 173
Acknowledgments 175
References 175
Index 180
Measuring the Charge and Spin States of Electrons on Individual Dopant Atoms in Silicon 181
Quantum Computing with Phosphorus in Silicon 182
Electronic Donor States of Phosphorus in Silicon 183
Coupled Pairs of Phosphorus Donors as Charge Qubits 183
Coherent Manipulation 184
Controlled Single-Ion Implantation 185
Single-Ion Detection with Integrated p-i-n Diodes 185
Integration with Nanofabrication 186
Charge Sensing with Superconducting RF-SETs 186
Layout and Performance of RF-SET Measurements 187
Charge Transfer in Atomically Doped Devices 188
Initialization and Readout with Schottky Contacts 189
Contacting Atomically Doped Devices 189
Magnetic Resonance in Nanoscale Implanted Devices 190
Summary and Outlook 192
Acknowledgements 192
References 193
Index 194
Electron Spin as a Spectrometer of Nuclear-Spin Noise and Other Fluctuations 195
Introduction 195
Noise, Relaxation, and Decoherence 198
The Bloch-Wangsness-Redfield Master Equation 198
Finite Frequency Phase Fluctuations and Coherence Decay in the Semiclassical-Gaussian Approximation 200
General Results for the Short-Time Behavior 203
Example: The Gauss-Markov Model 204
A Train of Hahn Echoes: The Carr-Purcell Sequence and Coherence Control 205
Loss of Visibility Due to High-Frequency Noise 206
Single-Spin Measurement Versus Ensemble Experiments: Different Coherence Times? 206
Electron-Spin Evolution Due to Nuclear Spins: Isotropic and Anisotropic Hyperfine Interactions, Internuclear Couplings and the Secular Approximation 208
The Electron-Nuclear Spin Hamiltonian 208
Electron-Nuclear-Spin Evolution in the Secular Approximation 210
Inhomogeneous Broadening Due to the Isotropic Hyperfine Interaction 211
Beyond the Secular Approximation: Nuclear-Nuclear Interactions Mediated by the Electron Spin Hyperfine Interaction 212
Microscopic Calculation of the Nuclear-Spin Noise Spectrum and Electron-Spin Decoherence 214
Nuclear-Spin Noise 215
Mean Field Theory of Noise Broadening: Quasiparticle Lifetimes 218
Electron Spin-Echo Decay of a Phosphorus Impurity in Silicon: Comparison with Experiment 221
Effective-Mass Model for a Phosphorus Impurity in Silicon 221
Explicit Calculations of the Nuclear-Spin Noise Spectrum and Electron Spin-Echo Decay of a Phosphorus Impurity in Silicon 222
Conclusions and Outlook for the Future 227
Acknowledgments 229
References 230
Index 232
A Robust and Fast Method to Compute Shallow States without Adjustable Parameters: Simulations for a Silicon-Based Qubit 233
Shallow Impurities in an External Field 235
Envelope Function Approximation 236
The Central-Cell Correction 237
Numerical Basis Set 238
Phosphorous Impurity in Silicon 238
Bulk Ingredients 239
Theoretical Results: Si:P 239
The Core-Correction Contribution 240
Stark Effect 241
Electric-Field Dependence of Superhyperfine Constants 244
Confinement Effects 246
Conclusions 249
References 250
Index 251
Photon-Assisted Tunneling in Quantum Dots 252
Introduction 252
Theory of Photon-Assisted Tunneling in Quantum Dots 253
Hamiltonian Formalism of Tunneling under Microwave Irradiation 254
Tunneling in Quantum Dots under Microwave Irradiation 255
Typical Regimes of Operation 257
Experimental Results in III-V Heterostructure Quantum Dots 258
Experimental Setup 258
Single Dots 258
Double Dots 259
Group IV Heterostructure Quantum Dots 261
Experimental Setup 261
Experimental Results 262
Si/SiO2 nanoFET Quantum Dots 263
Experimental Setup 263
Experimental Results 264
Conclusions 267
References 268
Index 269
Index 270