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MA: Fachverband Magnetismus
MA 42: Topological Insulators (jointly with TT, HL)
MA 42.1: Vortrag
Mittwoch, 16. März 2011, 16:45–17:00, HSZ 04
Complex spin structure of the topological insulator Bi2Te3(0001) — •Jürgen Henk1, Arthur Ernst1, Sergey V. Eremeev2, and Evgueni V. Chulkov2 — 1Max Planck Institute of Microstructure Physics, Halle, Germany — 2Donostia International Physics Center, San Sebastian, Spain
Topological insulators — like Bi2Te3(0001) — show a unique surface electronic structure. A model Hamiltonian [1] describes well the anisotropic dispersion of the Dirac state, as is evident from agreement with photoemission experiments (e. g. [2]). The spin of the Dirac state shows a circular arrangement in the momentum distribution, even in the presence of warping.
We prove by relativistic first-principles calculations that the spin structure of the Dirac state in Bi2Te3(0001) is much more complicated than that derived from model calculations. First, all three spin components at the top Te layer are reversed with respect to those in the subsurface layers, and, second, the circular spin structure is destroyed at the cusps of warped momentum distributions, showing a vortex-like structure. Our findings are explained by hybridization of p orbitals in the topmost quintuple layer and may have implications for spintronic applications.
[1] L. Fu, Phys. Rev. Lett. 103 (2009) 266801.
[2] D. Hsieh et al, Phys. Rev. Lett. 103 (2009) 146401.