Memory Effect in a Topological Surface State of Bi sub(2)Te sub(2)Se

We demonstrate the controllable local manipulation of the Dirac surface state in a topological insulator, Bi sub(2)Te sub(2)Se, which has suppressed bulk carrier density. Using scanning tunneling microscopy/spectroscopy under magnetic fields, we observe Landau levels of the Dirac surface state in th...

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Bibliographic Details
Published inACS nano Vol. 7; no. 5; pp. 4105 - 4110-4105-4110
Main Authors Fu, Ying-Shuang, Hanaguri, Tetsuo, Yamamoto, Shuhei, Igarashi, Kyushiro, Takagi, Hidenori, Sasagawa, Takao
Format Journal Article
LanguageEnglish
Published 08.05.2013
Subjects
Bias
Carrier density
Conductance
Electric potential
Magnetic fields
Nanostructure
Spectra
Topology
Voltage
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Summary:We demonstrate the controllable local manipulation of the Dirac surface state in a topological insulator, Bi sub(2)Te sub(2)Se, which has suppressed bulk carrier density. Using scanning tunneling microscopy/spectroscopy under magnetic fields, we observe Landau levels of the Dirac surface state in the conductance spectra. The Landau levels start to shift in their energy once the bias voltage between the tip and the sample exceeds a threshold value. The amount of shift depends on the history of bias ramping. As a result, conductance spectra show noticeable hysteresis, giving rise to a memory effect. The conductance images exhibit spatially inhomogeneous patterns which can also be controlled by the bias voltage in a reproducible way. On the basis of these observations, we argue that the memory effect is associated with the tip-induced local charging effect which is pinned by the defect-generated random potential. Our study opens up a new avenue to controlling the topological surface state.
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ISSN:1936-0851
1936-086X
DOI:10.1021/nn400378f