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TT: Fachverband Tiefe Temperaturen
TT 58: Transport: Poster Session
TT 58.50: Poster
Wednesday, March 9, 2016, 15:00–18:30, Poster D
Optical Measurement of Carrier Mobilities in the Topological Insulator BiSbTeSe2 — •Henning Kuhn, Jingyi Zhu, Matteo Montagnese, Zhiwei Wang, Yoichi Ando, and Paul H.M. van Loosdrecht — 2.Physikalisches Institut, Universität zu Köln
Transient Grating Spectroscopy, an ultrafast pump-probe technique, is employed to investigate the non-equilibrium transport properties of the topological insulator (TI) BiSbTeSe2.
An optically generated periodic modulation pattern of electronic excitations is created at the surface of the TI and its decay is observed, both through the use of 100fs pulses from a mode locked Ti:Sapphire laser system. Experiments are performed in the temperature range from 10K to 300K using a heterodyne detection scheme, which, among other, show clear coherent phonon excitations. From the transient grating decay times, carrier diffusivities and thus carrier mobilities are extracted. The obtained temperature dependence of the mobility will be discussed in terms of the recently proposed puddle model, paying special attention to a potential contribution from surface carriers.