Table of Contents
Preface ix
Acknowledgements xi
1 Frontiers in device engineering 1
1.1 Introduction 1
1.2 Example: Optimal design of atomic clusters 3
1.3 Design in the age of quantum technology 6
1.4 Exploring nonintuitive design space 14
1.5 Mathematical formulation of optimal device design 15
1.6 Local optimization using the adjoint method 18
1.7 Global optimization 21
1.8 Summary 28
1.9 References 29
2 Atoms-up design 32
2.1 Manmade nanostructures 32
2.2 Long-range tight-binding model 35
2.3 Target functions and convergence criterion 36
2.4 Atoms-up design of tight-binding clusters in continuous configuration space 38
2.5 Optimal design in discrete configuration space 42
2.6 Optimization and search algorithms 45
2.7 Summary 48
2.8 References 49
3 Electron devices and electron transport 51
3.1 Introduction 51
3.2 Elastic electron transport and tunnel current 57
3.3 Local optimal device design using elastic electron transport and tunnel current 61
3.4 Inelastic electron transport 71
3.5 Summary 85
3.6 References 86
4 Aperiodic dielectric design 88
4.1 Introduction 88
4.2 Calculation of the scattered field 89
4.3 Optimization 91
4.4 Results 93
4.5 Efficient local optimization using the adjoint method 103
4.6 Finite difference frequency domain electromagnetic solver 104
4.7 Cost functional 107
4.8 Gradient-based optimization using the adjoint method 108
4.9 Results and comparison with experiment 109
4.10 References 120
5 Design at the classical-quantum boundary 123
5.1 Introduction 123
5.2 Non-local linear response theory 124
5.3 Dielectric response of a diatomic molecule 126
5.4 Dielectric response of small clusters 129
5.5 Dielectric response of a metallic rod 135
5.6 Response of inhomogeneous structures 137
5.7 Optimization 141
5.8 Summary and outlook 147
5.9 References 147
6 Robust optimization in high dimensions 149
6.1 Introduction 149
6.2 Unconstrained robust optimization 152
6.3 Constrained robust optimization 170
6.4 References 186
7 Mathematical framework for optimal design 189
7.1 Introduction 189
7.2 Constrained local optimal design 194
7.3 Local optimal design of an electronic device 204
7.4 Techniques for global optimization 228
7.5 Database of search iterations 237
7.6 Summary 244
7.7 References 244
8 Future directions 246
8.1 Introduction 246
8.2 Example: System complexity in a small laser 247
8.3 Sensitivity to atomic configuration 251
8.4 Realtime optimal design of molecules 257
8.5 The path to quantum engineering 258
8.6 Summary 259
8.7 References 260
Appendix A Global optimization algorithms 262
A.1 Introduction 262
A.2 Tabu search 262
A.3 Particle swarm algorithm 263
A.4 Simulated annealing 265
A.5 Two-phased algorithms 268
A.6 Clustering algorithms 269
A.7 Global optimization based on local techniques 272
A.8 Global smoothing 273
A.9 Stopping rules 274
A.10 References 275
About the authors 277
Index 281
