Dresden 2017 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 76: Poster Session: Transport 2

TT 76.20: Poster

Donnerstag, 23. März 2017, 15:00–19:00, P2-OG1

Gigantic negative magnetoresistance in the topological insulator TlBi_xSb_1−xTe₂ — •Oliver Breunig¹, Zhiwei Wang¹, Jonathan Lux², Achim Rosch², Alexey Taskin¹, and Yoichi Ando¹ — ¹Physics Institute II, University of Cologne — ²Institute for Theoretical Physics, University of Cologne

Recently the phenomenon of negative magnetoresistance (MR) gains increasing interest in the context of the chiral anomaly in Weyl semimetals. Here, we present a new mechanism leading to a large negative MR that is related to disorder in a compensated topological insulator. We have grown single crystals of the topological insulator material TlBi_xSb_1−xTe₂ by a modified Bridgman technique. For intermediate values x we find a bulk-insulating state and a surprisingly strong negative MR reaching 98% at low temperature and in applied magnetic fields of 14 T. Based on transport data and numerical simulations we show that the increased conductivity at high fields is due to the magnetic field-enhanced percolation of localized electronic states.