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HL: Fachverband Halbleiterphysik
HL 35: Poster I
HL 35.17: Poster
Dienstag, 8. März 2016, 15:00–19:00, Poster A
Combined structural, electronic and transport investigations on metallic and semiconducting micro flakes from a topological insulator Bi2Se3 single crystal — •Dominic Lawrenz1, Olivio Chiatti1, Christian Riha1, Marco Busch1, Franz Herling1, Srujana Dusari1, Jaime Sanchez-Barriga2, Anna Mogilatenko3, Lada V. Yashina4, Sergio Valencia2, Ahmet A. Ünal2, Oliver Rader2, and Saskia F. Fischer1 — 1Novel Materials Group, Institut für Physik, Humboldt Universität zu Berlin, D-12489 Berlin — 2Helmholtz-Zentrum-Berlin für Materialien und Energie, D-12489 Berlin — 3Ferdinand-Braun-Institut, D-12489 Berlin — 4Department of Chemistry, Moscow State University, 119992 Moscow, Russia
High-quality Bi2Se3 bulk and exfoliated micro flakes are investigated via temperature dependent magneto-transport measurements. To achieve a comprehensive picture, these results are combined with high resolution transmission electron microscopy, energy dispersive x-ray spectroscopy and photoemission electron microscopy to confirm the structure and stoichometry of bulk and flakes. A well-defined bulk band-gap and the presence of a single Dirac cone are proven by angle-resolved photoemission spectroscopy. We investigate Bi2Se3 in the regime of high electron density (>1019 cm−3) and find two-dimensional (2D) layered metallic transport in the Shubnikov-de Haas oscillations and quantized Hall resistance. In exfoliated micro flakes the low-field magneto-conductivity shows weak antilocalization that is analyzed in the Hikami-Larkin-Nagaoka (HLN) model for 2D systems.