@article{SessiBiswasBathonetal.2016,
  author    = {Sessi, Paolo and Biswas, Rudro R. and Bathon, Thomas and Storz, Oliver and Wilfert, Stefan and Barla, Alessandro and Kokh, Konstantin A. and Tereshchenko, Oleg E. and Fauth, Kai and Bode, Matthias and Balatsky, Alexander V.},
  title     = {Dual nature of magnetic dopants and competing trends in topological insulators},
  series = {Nature Communications},
  volume    = {7},
  journal   = {Nature Communications},
  doi       = {10.1038/ncomms12027},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-172704},
  year      = {2016},
  abstract  = {Topological insulators interacting with magnetic impurities have been reported to host several unconventional effects. These phenomena are described within the framework of gapping Dirac quasiparticles due to broken time-reversal symmetry. However, the overwhelming majority of studies demonstrate the presence of a finite density of states near the Dirac point even once topological insulators become magnetic. Here, we map the response of topological states to magnetic impurities at the atomic scale. We demonstrate that magnetic order and gapless states can coexist. We show how this is the result of the delicate balance between two opposite trends, that is, gap opening and emergence of a Dirac node impurity band, both induced by the magnetic dopants. Our results evidence a more intricate and rich scenario with respect to the once generally assumed, showing how different electronic and magnetic states may be generated and controlled in this fascinating class of materials.},
  language  = {en}
}
@article{KernreiterGovernaleZuelickeetal.2016,
  author    = {Kernreiter, T. and Governale, M. and Z{\"u}licke, U. and Hankiewicz, E. M.},
  title     = {Anomalous Spin Response and Virtual-Carrier-Mediated Magnetism in a Topological Insulator},
  series = {Physical Review X},
  volume    = {6},
  journal   = {Physical Review X},
  number    = {021010},
  doi       = {10.1103/PhysRevX.6.021010},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-166582},
  year      = {2016},
  abstract  = {We present a comprehensive theoretical study of the static spin response in HgTe quantum wells, revealing distinctive behavior for the topologically nontrivial inverted structure. Most strikingly, the q=0 (long-wavelength) spin susceptibility of the undoped topological-insulator system is constant and equal to the value found for the gapless Dirac-like structure, whereas the same quantity shows the typical decrease with increasing band gap in the normal-insulator regime. We discuss ramifications for the ordering of localized magnetic moments present in the quantum well, both in the insulating and electron-doped situations. The spin response of edge states is also considered, and we extract effective Land{\´e} g factors for the bulk and edge electrons. The variety of counterintuitive spin-response properties revealed in our study arises from the system's versatility in accessing situations where the charge-carrier dynamics can be governed by ordinary Schr{\"o}dinger-type physics; it mimics the behavior of chiral Dirac fermions or reflects the material's symmetry-protected topological order.},
  language  = {en}
}