Dresden 2017 – scientific programme
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O: Fachverband Oberflächenphysik
O 32: Focus Session: Charge Transport at Surfaces and Nanostructures with Multi-probe Techniques I
O 32.1: Invited Talk
Tuesday, March 21, 2017, 10:30–11:00, WIL C307
Electrical detection of spin-polarized transport on topological insulator via four-probe spectroscopy — •An-Ping Li1, Saban Hus1, Corentin Durand1, Xiaoguang Zhang1,2, Giang Nguyen1, and Yong Chen3 — 1Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA — 2University of Florida, Gainesville, FL 32611, USA — 3Purdue University, West Lafayette, IN 47907, USA
The electrical detection of spin-momentum-locking of topological surface states remains an experimental challenge. The difficulty is twofold. First, there is a lack of a convenient spin-dependent probing technique to measure the spin current. Second, it is hard to separate 2D surface conductivity from often unavoidable and more dominating 3D bulk contributions in transport experiments. Here we present a new method for detection of spin polarized currents in topological insulator, by using a spin-polarized four-probe spectroscopy on the in-situ cleaved Bi2Te2Se surfaces. The variable probe spacing measurements separate the surface 2D and bulk 3D conductions quantitatively, capable of distinguishing the vanishing Ohmic and non-dissipative spin-dependent electrochemical potentials. This method provides an alternative to the transport spectroscopy with lithographically defined contacts and enables us to access the intrinsic spin transport associated with pristine topological surface states. [1] A-P Li et al., Adv. Funct. Mater. 23 (2013), p. 2509. [2] C Durand et al., Nano Lett., 16 (2016), p. 2213. [3] S. Hus et al, to be submitted.