Regensburg 2016 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 46: Topological Insulators I
(Joint session of DS and HL, organized by HL)

DS 46.3: Vortrag

Donnerstag, 10. März 2016, 15:15–15:30, H10

Negative Magnetoresistance of TlBi_xSb_1−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 TlBi_xSb_1−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 TlBi_xSb_1−xTe₂ and discuss the origin of the observed large negative magnetoresistance.