Non-equilibrium Many-body States in Carbon Nanotube Quantum Dots (eBook)

Supervisor’s Foreword 6
List of Publication 8
Acknowledgements 9
Contents 10
1 Introduction 13
1.1 Mesoscopic Physics 1Datta,1Heikkila 13
1.2 Landauer-Büttiker Formula 1Datta 14
1.3 Quantum Dot 16
1.3.1 Quantum Dot Structures and Materials 16
1.3.2 Quantum Dot Transport 16
1.4 Carbon Nanotube 19
1.4.1 Basic Properties of Carbon Nanotube 19
1.4.2 CNT QDs and Magnetic Spectroscopy 1Laird,1Fujiwara 20
1.5 Kondo Effect 22
1.5.1 Kondo Effect in a QD 23
1.5.2 Pervious Experiments 27
1.6 Josephson Junction 27
1.6.1 Andreev Reflections 1Octavio 28
1.6.2 Andreev Bound States 1Nazarov 32
1.6.3 Multiple Andreev Reflections 34
1.7 Current Noise 36
1.7.1 Thermal Noise and Shot Noise 1Glattli,1Blanter 36
References 37
2 Experimental Methods 41
2.1 Fabrication Method 41
2.2 Measurement Setup 42
2.2.1 Dilution Refrigerator 42
2.2.2 Conductance Measurement 42
2.2.3 Current Noise Measurement 43
2.3 Characteristics of the CNT QD 44
2.3.1 Conductance Properties (Normal State) 44
2.3.2 Conductance Properties (Superconducting State) 45
2.3.3 Current Noise Properties 46
References 47
3 Non-equilibrium Fluctuations in Strongly Correlated Kondo States 49
3.1 Non-equilibrium Kondo Effect and Shot Noise 49
3.2 Experimental Results 51
3.2.1 Kondo Characteristics 51
3.2.2 The Wilson Ratio Extracted from the Scaling Laws 52
3.2.3 Shot Noise in the Linear Regime and Fano Factor 54
3.2.4 Shot Noise in the Nonlinear Regime and Wilson Ratio 55
3.2.5 Magnetic Field and Temperature Dependence of Shot Noise 56
3.2.6 Conclusion 56
References 57
4 Non-equilibrium Fluctuations Along Symmetry Crossover in a Kondo-Correlated Quantum Dot 58
4.1 SU(4) Kondo Effect 58
4.2 Symmetry Crossover in a Kondo QD 60
4.3 Extraction of the Angle of the Magnetic Field 61
4.4 SU(4) Kondo Effect at Zero Magnetic Field 63
4.4.1 SU(4) Kondo Effects Properties 63
4.4.2 SU(4) Kondo Shot Noise in the Linear Regime 64
4.4.3 SU(4) Kondo Shot Noise in the Nonlinear Regime 65
4.5 Symmetry Crossover From SU(4) to SU(2) 66
4.5.1 Conductance Measurement and NRG Calculations 66
4.5.2 Shot Noise in the Linear Regime Along the Crossover 66
4.5.3 Shot Noise in the Nonlinear Regime Along the Crossover 67
4.5.4 Conclusion 69
References 70
5 Kondo–Andreev Competing System in Carbon Nanotube 71
5.1 Interplay Between Kondo Effect and Superconductivity 71
5.2 Experimental Results 72
5.2.1 SU(2) Kondo Effects and Superconductivity 72
5.2.2 SU(4) Kondo Effects and Superconductivity 74
5.2.3 Conductance at the Same Filling 74
5.2.4 Shot Noise at the Same Filling 76
5.2.5 Perfect Transmission Regimes in the SU(2) and SU(4) Regimes 77
5.2.6 Comparison Between Experiment and Simulation 77
5.2.7 Remark on the Absence of Supercurrent 79
5.2.8 Conclusion 80
References 81
6 Summary 83
6.1 Non-equilibrium Fluctuations in Strongly Correlated Kondo States 83
6.2 Non-equilibrium Fluctuations Along Symmetry Crossover in a Kondo Correlated Quantum Dot 84
6.3 Kondo–Andreev Competing System in Carbon Nanotube 85