Regensburg 2013 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 61: Topological Insulators 4 (jointly with DS, HL, MA, and O)

TT 61.3: Vortrag

Donnerstag, 14. März 2013, 15:45–16:00, H18

Magnetotransport in MBE-grown topological insulator (Bi_1−xSb_x)₂Te₃ thin films — •Christian Weyrich¹, Tobias Merzenich¹, Igor E. Batov^1,2, Gregor Mussler¹, Jörn Kampmeier¹, Yulieth Arango¹, Detlev Grützmacher¹, Thomas Schäpers^1,3, and Jürgen Schubert¹ — ¹Peter Grünberg Institute (PGI-9), Research Centre Jülich GmbH, 52425 Jülich, Germany — ²Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, 142432, Moscow Distr., Russia — ³II. Physikalisches Institut, RWTH Aachen University, 52056 Aachen, Germany

We report on the magnetotransport study of topological insulator (Bi_1−xSb_x)₂Te₃ thin films. The films were grown on a silicon on insulator (SOI) substrate with a Si(111)-layer on top by molecular beam epitaxy. In Bi₂Te₃ samples, we observed a positive magnetoresistance at low magnetic fields with a cusplike minimum at B = 0 (weak antilocalization) as well as positive magnetoresistance in the entire magnetic field range (up to 12 T). The weak antilocalization effect disappears when an in-plane field is applied, showing the anisotropy between the transport parallel and perpendicular to the quintuple-layers. The estimated phase coherent lengths up to 250 nm at low temperatures are comparable to those previously obtained for Bi₂Te₃. The magnetotransport measurements were also performed on MBE-grown films of Sb₂Te₃ (p-doped) as well as on the ternary compound (Bi_1−xSb_x)₂Te₃ (0<x<1). A transition from n- to p-doping depending on x has been seen in the measurements.