Electronic, magnetic and transport properties of topolgical insulators: An ab initio description

Topological insulators are materials in which the spin-orbit interaction leads to protected metallic surface or edge states as a consequence of the topology of the bulk electronic structure. We will concentrate on ab initio descriptions of three-dimensional topological insulators (Bi2Te3, Bi2Se3, HgTe on CdTe) by means of bulk and surface electronic structure calculations, taking into account periodic and open boundary conditions. We will provide a tool to investigate the topological invariants. By means of doping, intercalation and adlayer deposition with nonmagnetic materials we will tailor the electronic properties with respect to gap size and position of the Dirac state. The breakdown of the topological character is studied by doping and adlayer deposition of magnetic material, investigating the magnetic order and magnetocrystalline anisotropy. Based on the electronic structure of the unperturbed and perturbed systems under consideration, we study the influence of the Dirac state on conductivity, thermopower and spin Hall effect as well as on spin- and angle-resolved photoemission intensities.