Doctoral Thesis: Topological insulators and semimetals: theory for bulk and surface electronic properties

In the present thesis, electronic properties of topologically non-trivial materials are investigated. Theoretical calculations of electronic band structures for various system geometries are performed by means of an ab initio based Tight-Binding model. The related topological invariants are calculated for both insulating and metallic materials by methods based on the Berry-phase concept. Topological phase diagrams are generated, showing the different topological phases which can be entered by the examined systems under a change of external parameters, such as strain, disorder or magnetic field. These results are confirmed by simultaneous investigations of the surface electronic band structure featuring topologically protected surface states in the case of non-trivial topological phases.

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