Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 90: Topological Insulators I
O 90.3: Vortrag
Donnerstag, 10. März 2016, 15:15–15:30, H10
Negative Magnetoresistance of TlBixSb1−xTe2 — •Oliver Breunig, Zhiwei Wang, Fan Yang, Alexey Taskin, and Yoichi Ando — II. Physikalisches Institut, Universität zu Köln
In the family of the ternary II-V-VI2 compounds several materials have been identified as topological insulators. In the n-type TlBiTe2 a topological surface state has been found, yet it is hardly accessible for transport studies due to the overlap with the bulk bands. Theoretical studies suggest that upon substituting Bi by Sb a narrow bulk band gap opens while preserving a single Dirac cone at the Γ point, leading to a possible realization of a bulk-insulating system with an exposed Dirac point.
Single crystals of TlBixSb1−xTe2 were grown by a modified Bridgman technique using high-purity starting materials. They were characterized by ICP/EDX as well as transport measurements. For intermediate values x we find insulating transport properties and a surprisingly strong negative magnetoresistance. We present our crystal growth results of TlBixSb1−xTe2 and discuss the origin of the observed large negative magnetoresistance.