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Gaku Eguchi, K. Kuroda, A. Kimura, S. Paschen:
"Surface phonon scattering in the topological insulator TlBiSe2";
Vortrag: Japan Physical Society 2016 fall meeting, Kanazawa, Japan; 13.09.2016 - 16.09.2016.

The discovery of three-dimensional (3D) topological insulators has established a new trend of material research, and a large number of investigations have been conducted not only in basic research but also for practical applications. A 3D topological insulator exhibits a metallic sur- face state protected by time-reversal symmetry, and the state consists of spin-polarized massless Dirac fermions. In electric transport, these remarkable features result in high-mobility carriers confined at surfaces. A number of 3D topological insulators has been reported or suggested within the past years [1], however, almost all of them exhibit additional bulk electronic bands at the Fermi level. This results in the dominance of bulk metallic conduction and obscures the contribution of surface conduction. A remarkable achievement was the realization of an isolated surface band, which was first demonstrated in Bi2(Se, Te)3 [1]. However, an instability of the Fermi level has also been revealed, and for this reason details of the surface trans- port remain unclear. Recently, an isolated surface band has also been realized in TlBiSe2 [2]. TlBiSe2 shows excellent stability and reproducibility in transport experiments [3]. Therefore, we consider TlBiSe2 as an ideal system to reveal a surface transport properties.
In this presentation, we report a transport study of bulk metallic and bulk insulating TlBiSe2 between room temperature and 20 mK. Signals originating from the surface were separated using a recently-proposed analysis method for a two-carrier model [4]. Based on the results, scattering mechanisms, phase coherence, and Landau quantization of the surface state are discussed.