Dresden 2017 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 75: Poster Session: Transport 1

TT 75.12: Poster

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

Magnetotransport in Topological Insulator Bi_1.5Sb_0.5Te_1.7Se_1.3 — •Priyamvada Bhaskar, André Dankert, Dmitrii Khokhriakov, and Saroj Dash — Chalmers University of Technology, Göteborg, Sweden

Topological insulators (TIs) provide an excellent platform to study topological quantum physics and exploring spintronic applications due to their unique gap-less spin polarized helical metallic surface states. We explore novel semiconducting TI material Bi_1.5Sb_0.5Te_1.7Se_1.3 (BSTS) and report weak-anti localization (WAL) and quantum oscillations originating from surface states. Further, spin signals originating from spin-momentum locking were observed up to room temperature. From the temperature dependence of phase coherence length and the angle dependence of universal conductance fluctuations (UCF) it was inferred that the observed transport mechanisms originate from 2D, although coupling to the bulk leading to the formation of a single 2D channel cannot be ruled out. Although the angle dependence of WAL indicates surface state contribution, Shubnikov-de Haas oscillations provide for a low surface carrier concentration. However, magnetotransport in BSTS shows high spin polarization, thus showing promise as a spintronic TI. These studies provide a platform to pursue exotic physics and novel device applications predicted for TIs and its heterostructures with other 2D materials.