Indications of surface-dominated transport in single crystalline nanoflake devices of topological insulator Bi_{1.5}Sb_{0.5}Te_{1.8}Se_{1.2}
We report experimental evidence of surface-dominated transport in single crystalline nanoflake devices of topological insulator Bi1.5Sb0.5Te1.8Se1.2 (BSTS). The resistivity measurements show dramatic differences between the nanoflake devices and bulk single crystal. Based on a two-channel model, t...
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| Main Authors: | , , , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | English |
| Published: |
2013
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| Subjects: | |
| Online Access: | https://hdl.handle.net/10356/96430 http://hdl.handle.net/10220/9916 |
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| Institution: | Nanyang Technological University |
| Language: | English |
| Summary: | We report experimental evidence of surface-dominated transport in single crystalline nanoflake devices
of topological insulator Bi1.5Sb0.5Te1.8Se1.2 (BSTS). The resistivity measurements show dramatic differences
between the nanoflake devices and bulk single crystal. Based on a two-channel model, the analysis on the
resistivity and Hall resistance indicates that ∼99% surface transport contribution can be realized in 200 nm-thick
BSTS nanoflake devices. Using a standard back gate with SiO2 as a dielectric layer, a pronounced ambipolar
electric field effect was observed in devices fabricated with 100–200 nm thick flakes.Moreover, angle-dependent
magnetoresistances of a nanoflake device with a thickness of 596 nanometers are fitted to a universal curve for
the perpendicular component of the applied magnetic field. The value of phase coherence length obtained from
two-dimensional weak antilocalization fitting further confirmed the surface dominated transport. Our results open
a path for realization of electric and spintronic devices based on the topological helical surface states. |
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