Berlin 2015 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 39: Posters II (Topological insulators; Graphene; Spintronics and spin physics; Quantum information science)
HL 39.6: Poster
Tuesday, March 17, 2015, 14:00–20:00, Poster F
Comprehensive study of undoped Bi2Se3 microflakes via structural, chemical and transport investigations — •Dominic Lawrenz1, Christian Riha1, Franz Herling1, Olivio Chiatti1, Srujana Dusari1, Jaime Sanchez-Barriga2, Anna Mogilatenko3, Lada Yashina4, Sergio Valencia2, Ahmet Ünal2, Oliver Rader2, and Saskia Fischer1 — 1Neue Materialien, Institut für Physik, Humboldt Universität zu Berlin, 12489 Berlin, Germany — 2Helmholtz-Zentrum-Berlin für Materialien und Energie, 12489 Berlin, Germany — 3Ferdinand-Braun-Institut, 12489 Berlin, Germany — 4Department of Chemistry, Moscow State University, 119992 Moscow, Russia
Surface states of topological insulators are expected to show peculiar electrical transport properties [1]. The remaining bulk conductivity, however, renders these elusive in transport measurements so far.
A combined investigation of single-crystalline Bi2Se3 was undertaken to obtain a comprehensive picture. The band structure of the bulk material was investigated via ARPES. Flakes from the bulk to the thin-film range (thicknesses from 270 nm to 70 nm) were then exfoliated. Their crystal structure was investigated by HRTEM and the chemical composition by EDX and X-PEEM. Hall measurements of the conductivity were undertaken to determine the charge carrier mobility and density. Our results confirm the high quality of the material. The temperature dependence of the conductivity and magnetoresistance down to 0.3 K are presented and discussed.
[1] Hasan, Kane, Rev. Mod. Phys. 82, 3045 (2010)