Thermal Transport in Strongly Correlated Rare-Earth Intermetallic Compounds (eBook)

Supervisor’s Foreword 6
Abstract 9
Acknowledgments 10
Contents 13
Symbols 16
Abbreviations 18
1 Preamble 19
Reference 22
2 Introduction and Theoretical Background 23
2.1 Fermi Liquid 23
2.2 The Kondo Effect in 4f Electron Systems 25
2.2.1 Single-Ion Kondo Effect 25
2.2.2 Kondo Lattice 27
2.2.3 RKKY Interaction and Doniach Diagram 28
2.3 Classical Phase Transitions 29
2.4 Quantum Phase Transitions 30
2.5 Topological Transitions 32
2.6 Superconductivity 36
2.6.1 Properties of Conventional Superconductors 37
2.6.2 Properties of Unconventional Superconductors 40
2.6.3 Multiband Superconductivity 40
2.7 Transport in Solids 41
2.7.1 Boltzmann Equation 42
2.7.2 Thermal Conductivity 43
2.7.3 Wiedemann-Franz Law 45
2.7.4 Thermopower 46
References 48
3 Experimental Techniques for Transport Measurements 50
3.1 General Principle of Thermal Transport in a Dilution Refrigerator 50
3.2 The Three Set-Ups Used 51
3.3 Measurement Procedure---Steady State 53
3.4 Measurement Procedure---Pseudo AC 54
3.5 Origin and Estimation of Measurement Uncertainties 56
References 59
4 The Wiedemann-Franz Law in YbRh2Si2 60
4.1 Quantum Criticality in YbRh2Si2---Phenomenology 60
4.2 Quantum Criticality in YbRh2Si2---Theoretical Concepts 63
4.2.1 The Kondo-Breakdown Scenario 63
4.2.2 The Lifshitz Scenario 64
4.2.3 Critical Quasiparticle Theory 65
4.3 Motivation 65
4.4 Experimental Methods 66
4.5 Thermal and Electrical Transport 67
4.5.1 Phonon Contribution 67
4.5.2 Low-Temperature Data and the Wiedemann-Franz Law 69
4.5.3 Comparison with Results from Other Groups 74
4.6 Conclusion 77
References 78
5 Kondo Lattices in Magnetic Field 81
5.1 Introduction and Motivation 81
5.2 Experimental Methods 83
5.3 CeRu2Si2 83
5.3.1 The Metamagnetic Transition 84
5.3.2 Transport Data 84
5.4 YbRh2Si2 87
5.4.1 The High-Field Transition 87
5.4.2 Transport Data 88
5.4.3 Renormalized Band Structure Calculations for YbRh2Si2 89
5.5 Rigid-Band-Shift Models for the Field-Induced Transitions in CeRu2Si2 and YbRh2Si2 92
5.5.1 Transport Signatures 93
5.5.2 Thermodynamic Signatures 95
5.6 The Mott Formula in CeRu2Si2 and YbRh2Si2 96
5.6.1 General Approach 96
5.6.2 Phonon Drag 97
5.6.3 Validity in YbRh2Si2 but not in CeRu2Si2 98
5.6.4 Comparison of Thermopower and Density of States in YbRh2Si2 101
5.6.5 The q Ratio 102
5.7 Conclusion 103
References 105
6 The Superconducting Order Parameter of LaPt4Ge12 109
6.1 Introduction and Motivation 109
6.2 Experimental Methods 111
6.3 Resistivity 112
6.4 Specific Heat 112
6.5 Thermal Conductivity 114
6.5.1 T Dependence of the Thermal Conductivity 114
6.5.2 H Dependence of the Thermal Conductivity 116
6.5.3 Field-Angle Dependence of the Thermal Conductivity 122
6.6 Conclusion 126
References 126
7 Summary and Outlook 129
Curriculum Vitae 132
Professional Career 132
Education 132
List of Publications 132