@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} }