CONTENTS -- Preface -- 1 The Concept of Quantum-Dot Cellular Automata -- 1.1 Needed: A New Device Paradigm for the Nanoscale -- 1.2 The Physical Representation of Information -- 1.3 Dots in QCA -- 1.3.1 Metal dots -- 1.3.2 Molecular dots -- 1.3.3 Semiconductor dots -- 1.4 QCA Cells -- 1.5 The Quantum-Dot Cellular Automata Paradigm -- 1.6 Clocked QCA Cells -- 1.7 Clocked QCA Shift Devices -- 1.8 Power Gain -- 1.9 Robustness against Thermal Errors and Defects -- 1.10 Conclusions -- References -- 2 QCA Simulation with the Occupation-Number Hamiltonian -- 2.1 Introduction -- 2.2 Formulation of the Occupation-Number Hamiltonian -- 2.3 Diagonalization of the Occupation-Number Hamiltonian -- 2.4 Application to the Evaluation of the Effects of Geometric Asymmetry on the Cell-to-Cell Response Function -- References -- 3 Realistic Time-Independent Models of a QCA Cell -- 3.1 Introduction -- 3.2 Heterostructure with a Uniform Gate -- 3.3 Linear Gate -- 3.4 Linear Gate Deposited on Etched Surface -- 3.5 Modeling of a Complete QCA Cell -- 3.6 The Configuration-Interaction Method -- 3.6.1 Cell denned with a hole-array gate -- 3.6.2 Multiple-gate cell -- 3.7 Analysis of Cells with more than 2 Electrons -- 3.7.1 Many-electron driver cell -- 3.7.2 Semiclassical model -- 3.7.3 Many-electron driver cell -- 3.8 Analysis of Polarization Propagation along a Semiconductor-Based Quantum Cellular Automaton Chain -- 3.8.1 Model of a three-cell chain -- 3.9 Results -- References -- 4 Time-Independent Simulation of QCA Circuits -- 4.1 Introduction -- 4.2 Semiclassical Model of QCA Circuits -- 4.3 Thermal Behavior -- 4.4 Analytical Model -- 4.4.1 Numerical simulation of more complex circuits -- References.

5 Simulation of the Time-Dependent Behavior of QCA Circuits with the Occupation-Number Hamiltonian -- 5.1 Introduction -- 5.2 Modeling of Chains of Quantum Cells -- 5.3 Time Evolution of Polarization for a Chain of QCA Cells without Dissipation -- 5.4 Time Evolution of Polarization for a Chain of QCA Cells with Dissipation -- 5.5 Imperfections: Variable Coupling Strength Defects Stray Charges -- 5.5.1 Variations of the intercellular distances -- 5.5.2 Defects in interdot barriers -- 5.5.3 Effect of stray charges -- References -- 6 Time-Dependent Analysis of QCA Circuits with the Monte Carlo Method -- 6.1 Introduction -- 6.2 Six-Dot QCA Cell -- 6.2.1 Transition rates for a semi-cell -- 6.3 Analysis of the Parameter Space -- 6.3.1 Tunneling rate -- 6.3.2 Calculation of the energy imbalance -- 6.4 Simulation of Clocked and Nonclocked Devices -- 6.4.1 QCA circuit simulator -- 6.4.2 Simulation strategy -- 6.4.3 Binary wire simulations -- 6.4.4 Operation of a logic gate -- 6.5 Discussion -- References -- 7 Implementation of QCA Cells with SOI Technology -- 7.1 Advantages of the SOI Material System -- 7.2 Fabrication of Si-Nanostructures -- 7.3 Experiments with the SOI Material System -- 7.4 Electrical Characterization of Double Dots -- 7.5 Electrical Characterization of a 4 Dot QCA Cell -- 7.6 Concept of an Experiment for the Detection of QCA Operation -- 7.7 Simulations -- 7.8 Possible Improvements -- References -- 8 Implementation of QCA Cells in GaAs Technology -- 8.1 Introduction -- 8.2 Nanofabrication of GaAs Devices -- 8.3 Evaluation of the Achievable Precision -- 8.4 Electrical Characterization of QPCs -- 8.5 Modeling of Quantum Point Contacts: The Issue of Boundary Conditions -- 8.6 Electron Decay from an Isolated Quantum Dot -- 8.6.1 Lifetimes of the experimentally studied dot.

8.6.2 Statistical analysis of the experimental data -- 8.6.3 First decays -- 8.6.4 Later decays -- 8.6.5 Modeling of electron decay from the isolated quantum dot -- 8.6.6 Theoretical framework -- 8.6.7 Equilibrium dot -- 8.6.8 Dot with excess electrons -- 8.6.9 Quasibound states of the dot -- 8.6.10 Results and discussion -- References -- 9 Non-Invasive Charge Detectors -- 9.1 Introduction -- 9.2 Experiments on a Double Dot System with Non-Invasive Detector -- 9.3 Numerical Simulation of the Dot-Detector System -- 9.4 Determining the Operation of a AlGaAs-GaAs QCA Cell -- 9.5 Conclusion -- References -- 10 Metal Dot QCA -- 10.1 Introduction -- 10.2 QCA Cell -- 10.3 Clocked QCA Devices Fabricated Using Metal Tunnel Junctions -- 10.4 Charging Process in QCA Half-Cell -- 10.5 QCA Latch Operation -- 10.6 Two Stage QCA Shift Register - a Clocked QCA Cell -- 10.7 Simulation of a Multi-Stage Shift Register -- 10.8 QCA Power Gain -- References -- 11 Molecular QCA -- 11.1 Introduction -- 11.2 Aviram's Molecule: A Simple Model System -- 11.3 A Functioning Two-Dot Molecular QCA Cell -- 11.4 A Four-Dot Molecular QCA Cell -- 11.5 Conclusions -- References -- 12 Magnetic Quantum-Dot Cellular Automata (MQCA) -- 12.1 Introduction -- 12.2 Magnetic QCA Structures -- 12.3 Modeling of Magnetic QCA Arrays -- 12.4 Conclusion -- References -- 13 Final Remarks and Future Perspectives -- Index.