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Bulk and surface electron transport in topological insulator candidate YbB6–δ |
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| Authors: | Vladimir V Glushkov Alexey D Bozhko Alexey V Bogach Sergey V Demishev Anatoliy V Dukhnenko Volodimir B Filipov Mikhail V Kondrin Alexey V Kuznetsov Ilia I Sannikov Alexey V Semeno Natalya Yu Shitsevalova Valeriy V Voronov Nikolay E Sluchanko |
| Affiliation: | 1. Prokhorov General Physics Institute of RAS, Moscow, Russia;2. Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, Russia;3. Frantsevich Institute for Problems of Materials Science NAS, Kiev, Ukraine;4. Vereshchagin Institute of High Pressure Physics of RAS, Troitsk, Moscow, Russia;5. National Research Nuclear University ”MEPhI”, Moscow, Russia |
| Abstract: | We report the study of transport and magnetic properties of the YbB6–δsingle crystals grown by inductive zone melting. A strong disparity in the low temperature resistivity, Seebeck and Hall coefficients is established for the samples with the different level of boron deficiency. The effective parameters of the charge transport in YbB6–δ are shown to depend on the concentration of intrinsic defects, which is estimated to range from 0.09% to 0.6%. The pronounced variation of Hall mobility μH found for bulk holes is induced by the decrease of transport relaxation time from τ ≈ 7.7 fs for YbB5.994 to τ ≈ 2.2 fs for YbB5.96. An extra contribution to conductivity from electrons with μH≈ –1000 cm2 V–1 s–1 and the very low concentration n /nYb≈ 10–6 discovered below 20 K for all the single crystals under investigation is suggested to arise from the surface electron states appeared in the inversion layer due to the band bending. (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) |
| Keywords: | hexaborides semiconductors topological insulators electron transport |
