Topological insulators are a novel phase of condensed matter physics with unique spin structures [1]. Due to strong spin-orbit interaction he bulk of the material is insulating, but at the surface spin-polarized edge states are formed. The Fermi level crossing of these surface states is protected by the topology of the material and time-reversal symmetry.
Spin and angle-resolved photoemission spectroscopy is a powerful tool for the characterization of topological insulators because it can simultaneously determine the topology and the details of the spin structure [2].
In order to fully utilize the promises which topological insulators hold for developments in spintronics and fundamental physics, it is important to gain control over the details of the spin structure. Here we will show how the spin structure is directly linked to the crystal structure and can thus be influenced by it. Especially the occurrence of an out-of-plane spin component increases the number of potential applications because of the less stringent requirements on the injected spin direction. Furthermore we will discuss the influence of the exact surface termination on the spin structure and the possibility to manipulate the electronic and spin structure.
[1] M.Z. Hasan and C.L. Kane, Reviews of Modern Physics 4, 82 (2010)
[2] For a review see: J. Hugo Dil, J. Phys.: Condens. Matter 21 403001 (2009)
