Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 53: Transport: Topological Insulators 3 (jointly with TT, MA)
HL 53.4: Vortrag
Mittwoch, 28. März 2012, 10:15–10:30, BH 334
Quantum transport in nanostructures of Bi2Se3-topological insulator — •Joseph Dufouleur1, Romain Giraud1, Andreas Teichgräber1, Silke Hample1, Stephan Neuhaus1, Barbara Eichler2, Oliver G. Schmidt2, and Bernd Büchner1 — 1Institute for Solid State Research - IFW Leibniz Institute, Helmholtzstr. 20, D-01069 Dresden, Germany — 2Institute for Integrative Nanosciences - IFW Leibniz Institute, Helmholtzstr. 20, D-01069 Dresden, Germany
Three-dimensional topological insulators belong to a new class of semiconductors with a large spin-orbit coupling which have spin-polarized Dirac fermions at their surface. In theory, these materials are insulating in the bulk, so that charge transport is only due to electronic surface states. In pratice, the Fermi energy often stands above or below the bulk band gap, due to uncontrolled defects formed during the growth of single crystals, or of epitaxial thin films or nanostructures. This makes the electrical properties of topologically-protected surface states difficult to measure, unless ultra-thin flakes of these materials are prepared.
To overcome this difficulty, we performed quantum transport measurement in ultra-thin Bi2Se3 flakes grown by CVD. We used e-beam litography technics to pattern Hall bars in the topological insulator. The measurements were done at low temperature and in an in-plane and perpendicular magnetic field up to 15 T.