Detection of the Spin-Chemical Potential in Topological Insulators Using Spin-Polarized Four-Probe STM

We demonstrate a new method for the detection of the spin-chemical potential in topological insulators using spin-polarized four-probe scanning tunneling microscopy on in situ cleaved Bi_{2}Te_{2}Se surfaces. Two-dimensional (2D) surface and 3D bulk conductions are separated quantitatively via varia...

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Bibliographic Details
Published in:Physical review letters 2017-09, Vol.119 (13), p.137202-137202, Article 137202
Main Authors: Hus, Saban M, Zhang, X-G, Nguyen, Giang D, Ko, Wonhee, Baddorf, Arthur P, Chen, Yong P, Li, An-Ping
Format: Article
Language:English
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Summary:We demonstrate a new method for the detection of the spin-chemical potential in topological insulators using spin-polarized four-probe scanning tunneling microscopy on in situ cleaved Bi_{2}Te_{2}Se surfaces. Two-dimensional (2D) surface and 3D bulk conductions are separated quantitatively via variable probe-spacing measurements, enabling the isolation of the nonvanishing spin-dependent electrochemical potential from the Ohmic contribution. This component is identified as the spin-chemical potential arising from the 2D charge current through the spin momentum locked topological surface states (TSS). This method provides a direct measurement of spin current generation efficiency and opens a new avenue to access the intrinsic spin transport associated with pristine TSS.
ISSN:0031-9007
1079-7114
DOI:10.1103/physrevlett.119.137202