Dresden 2014 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 101: Transport - Poster Session

TT 101.38: Poster

Thursday, April 3, 2014, 15:00–19:00, P2

Transition between n-type and p-type transport in MBE-grown topological insulator (Bi_1−xSb_x)₂Te₃ thin films — Tobias Merzenich¹, •Melissa Schall¹, Christian Weyrich¹, Igor E. Batov^1,2, Gregor Mussler¹, Jörn Kampmeier¹, Yulieth Arango¹, Jürgen Schubert¹, Thomas Schäpers^1,3, and Detlev Grützmacher¹ — 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 transition between n-type and p-type conduction in the ternary compound (Bi_1−xSb_x)₂Te₃ (0<x<1) films grown by molecular beam epitaxy. They were grown on silicon on insulator (SOI) substrates with Si(111)-top layer harbouring. A top-gate was used to deplete the intrinsic n-doped bulk. By performing Hall measurements on several samples with varying x, we obtain a change of sign of the Hall resistivity at x=0.43. This is attributed to compensation effects. For samples with x<0.43 we obtain a n-type conduction, i.e. an electron transport, whereas samples with x>0.43 show a p-type conduction, i.e. a hole transport. This transition is an evidence that the Fermi energy is initially located above the conduction band edge and is shifted into the valence band for higher Sb concentration.