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Dresden 2017 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 3: Transport: Topological Insulators (jointly with DS, MA, HL, O)

HL 3.2: Talk

Monday, March 20, 2017, 09:45–10:00, HSZ 204

Low-temperature magnetotransport in Mn-doped Bi2Se3 topological insulatorsV. Tkáč1, V. Komanicky2, R. Tarasenko1, M. Vališka1, V. Holý1, G. Springholz3, V. Sechovský1, and •J. Honolka41Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, CZ — 2Institute of Physics, P. J. Šafárik University, SK — 3Institute of Semiconductor and Solid State Physics, Johannes Kepler University, AT — 4Institute of Physics, Academy of Sciences of the Czech Republic, CZ

Magnetic impurities can break the time-reversal symmetry of 3D topological insulators (TI), thereby opening an energy gap Δ at the Dirac point of a topological surface state with large consequences for transport properties in the thin film limit. In magnetotransport a transition from weak antilocalisation to weak localisation is expected, strongly dependent on contributions from possible coexisting 2D quantum well and bulk states. We present a low-T magnetotransport study (T = 0.3 K - 300 K, Bmax = 14 T) of MBE-grown Bi2Se3 films of 20 nm - 500 nm thickness with varying Mn concentrations up to 8% and Curie temperatures TC = 5 − 7 K [1,2]. The results are interpreted following mainly theory by Lu et al. [3] as a competition of quantum corrections to the conductivity σ (phase coherence length lφT−1/2 ∼ 50−150nm for pure Bi2Se3) and 2D e-e interaction corrections both in the ferro- and paramagnetic phase.

[1] M. Valiska et al., Appl. Phys. Lett. 108, 262402 (2016).

[2] R. Tarasenko et al., Physica B 481, 262 (2016).

[3] H.-Z. Lu et al., Phys. Rev. Lett. 112, 146601 (2014).

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