Topological Insulators: Advances in Thermoelectricity, Orbital Dynamics and Axion Electrodynamics

Abstract

Topological materials (TMs) are a special class of quantum materials which include Topological Insulators (TIs), Chern Insulators (CIs), Weyl Semimetals, Topological Superconductors and Magnetic Topological Insulators (MTIs). Their non-trivial topology, which differs from the trivial one of conventional systems, give these systems singular thermoelectric and magnetoelectric transport properties. These properties are not only rich from the physical point of view but they can be technologically beneficial for different applications being used such as thermoelectrics, transistors, spintronic devices, superconductors, etc. The origin of this thesis lies in the study of the thermoelectric properties of topological insulators, currently the best thermoelectric materials. Our perspective is theoretical from the beginning given the lack of a microscopic theory in the literature which answers why these systems have such an efficient thermoelectric response, represented by their well known experimental figure of merit. This led us to explore other effects and interactions such as the electron-phonon coupling, thermal excitations, and other orbital magnetic effects and phenomena related to the axion electrodynamics, which are a consequence of their non-trivial topology and shall be developed in this thesis. In addition, we give a new interpretation to the physics of these systems by introducing the concept of a topological intrinsic field which is derived from the Berry curvature defined in the non-trivial topological bands of these materials.