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.

About the Author: Artem Pronin graduated from the Moscow Physics and Engineering Institute in 1994. His PhD research was conducted at the A. M. Prokhorov Institute of General Physics of the Russian Academy of Sciences, Moscow, and was devoted to infrared and THz spectroscopy of superconductors. During his PhD studies, he spent a research term at the University of Augsburg, and in 1998, he received his PhD in solid-state physics from the Moscow Institute of Physics and Technology. Afterwards, he held postdoctoral positions at McMaster University, Canada, at Leiden University in the Netherlands, and at the University of Leeds, UK. During these terms, he studied various optical spectroscopic methods and investigated a variety of materials, which exhibited electronic correlations. In 2006, he joined the High Magnetic Field Laboratory in Dresden, Germany, where he carried out experimental optical investigations in high magnetic fields before moving to the University of Stuttgart in 2015. There, he has been leading a group at the 1st Physics Institute, which investigates optical properties of different topological materials, particularly of Weyl and Dirac semimetals. Overall, Artem Pronin has more than 70 publications on infrared, THz, and dielectric properties of superconductors, materials with strong electronic correlations, and topological materials.