This book provides a model description for the electromagnetic response of topological nodal semimetals and summarizes recent experimental findings in these systems. Specifically, it discusses various types of topological semimetals – Dirac, Weyl, nodal-line, triple-point, and multifold semimetals – and provides description for the characteristic features of the linear electrodynamic response for all these types of materials.
Topological semimetals possess peculiar bulk electronic band structure, which leads to unusual electrodynamic response. For example, the low-energy inter-band optical conductivity of nodal semimetals is supposed to demonstrate power-law frequency dependence and the intra- and inter-band contributions to the conductivity are often mixed. Further, the magneto-optical response is also unusual, because of the non-equidistant spacing between the Landau levels. Finally, in semimetals with chiral electronic bands, e.g. in Weyl semimetals, the simultaneous application of parallel magnetic and electric fields leads to the chiral anomaly, i.e. to a misbalance between the electrons with diffident chiralities. This misbalance affects the electrodynamics properties of the material and can be detected optically. All these points are addressed here in detail.
The book is written for a wide audience of physicists, working in the field of topological condensed matter physics. It gives a pedagogical introduction enabling graduate students and non-experts to familiarize themselves with the subject.

lgli/1614.pdf

lgrsnf/1614.pdf

Pronin, Artem V.

Springer Nature Switzerland AG

Springer Series in Solid-State Sciences, 2023

Switzerland, Switzerland

producers:
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Preface 6
Acknowledgements 8
Contents 10
1 Theoretical Background 13
1.1 Berry Phases, Topological Indices, and Topological Electronic Bands 13
1.1.1 Relevance of Topology to Electronic Bands 13
1.1.2 Berry Phase, Berry Connection, and Berry Curvature 16
1.1.3 Time-Dependent Phase 19
1.1.4 ``Berryology'' in Electronic Bands 19
1.1.5 Wave Packets and Anomalous Velocity 21
1.1.6 Chern-Insulator State and Integer Quantum Hall Effects 22
1.1.7 Topological Insulators 26
1.1.8 Topological Semimetals 29
1.2 Electrodynamics of Topological Semimetals 32
1.2.1 Complex Optical Conductivity and Dielectric Function 32
1.2.2 Electronic Band Dispersion and Optical Conductivity 33
1.3 Chiral Anomaly as Seen in Optics 36
1.3.1 Chiral Anomaly in Steady Fields 36
1.3.2 Dynamic Chiral Anomaly 37
2 Nodal-Line Semimetals 40
2.1 ZrSiS 40
2.1.1 Broadband Spectroscopy 41
2.1.2 Magneto-Optical Response 48
2.1.3 Conclusions 53
3 Dirac and Weyl Semimetals 55
3.1 The Dirac Semimetal Cd3As2 55
3.1.1 Experiment 56
3.1.2 Kramers-Kronig Analysis and its Robustness 57
3.1.3 Experimental Results 58
3.1.4 Discussion 60
3.1.5 Conclusions 63
3.2 The Dirac Semimetal Au2Pb 64
3.2.1 Sample Preparation and Characterization 64
3.2.2 Optical Experiments 67
3.2.3 Results and Discussion 67
3.2.4 Conclusions 72
3.3 The Weyl Semimetal NbP 72
3.3.1 Introduction 72
3.3.2 Sample Preparation, Experimental and Computational Details 73
3.3.3 Results and Analysis 75
3.3.4 Conclusions 82
3.4 The Weyl Semimetal TaP 82
3.4.1 Results and Discussion 83
3.4.2 Conclusions 87
3.5 Chiral Anomaly in Weyl Semimetals 87
3.5.1 Chiral Anomaly in TaAs 87
3.5.2 Dynamic Chiral Anomaly in NbAs 91
4 Triple-Point Semimetals 92
4.1 GdPtBi—Broadband Optical Response 92
4.1.1 Introduction 92
4.1.2 Sample Preparation and Experimental Details 93
4.1.3 Experimental Results 94
4.1.4 Computations and Analysis 96
4.1.5 Conclusions 99
4.2 Chiral Anomaly in GdPtBi 99
4.3 YbPtBi 101
4.3.1 Introduction 101
4.3.2 Experiment 102
4.3.3 Results and Discussion 103
4.3.4 Conclusions 109
5 Multifold Semimetals 110
5.1 RhSi 111
5.1.1 Experiment 111
5.1.2 Results and Discussion 112
5.1.3 Conclusions 119
5.2 PdGa 119
5.2.1 Experiment 119
5.2.2 Calculations 120
5.2.3 Results and Discussion 120
5.2.4 Conclusions 126
6 Summary 127
Appendix A Experiment and Data Processing 128
A.1 Zero-Field Measurements 128
A.2 Measurements in Magnetic Field 129
References 130

Springer Series in Solid-State Sciences
Erscheinungsdatum: 18.08.2023

2024-04-16