Dresden 2014 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 55: Transport: Topological insulators I (organized by TT)

HL 55.2: Talk

Tuesday, April 1, 2014, 14:15–14:30, HSZ 304

Finite width effect on weak antilocalization in MBE grown Bi₂Te₃ thin films — •Christian Weyrich^1,2, Tobias Merzenich^1,2, Igor E. Batov³, Gregor Mussler^1,2, Jörn Kampmeier^1,2, Jürgen Schubert¹, Thomas Schäpers^1,2, and Detlev Grützmacher^1,2 — ¹Peter Grünberg Institute (PGI-9) and JARA-Fundamentals of Future Information Technology, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany — ²Virtual Institute for Topological Insulators (VITI), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany — ³Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, 142432, Moscow Distr., Russia

The weak antilocalization effect is measured in Bi₂Te₃ layers under various tilt angles of the magnetic field with respect to the layer surface. The investigated Bi₂Te₃ layer was prepared by molecular beam epitaxy. For a magnetic field oriented perpendicularly to the layer the weak antilocalization effect at different temperatures can be well-fitted by the Hikami-Larkin-Nagaoka model. From the fit a phase coherence length of about 200 nm is obtained at a temperature of 2 K. A clear signature of weak antilocalization is also observed when the magnetic field is oriented parallel to the Bi₂Te₃ layer. This effect is compared to classical models as well as a recently developed theory, which takes into account the finite penetration depth of the surface or interface states into the bulk.