Electric transport studies on topological insulators

This thesis presents transport experiments performed on topological insulators systems of Bi2Se3, Ca: Bi2Se3 and Bi1.5Sb0.5Te1.8Se1.2. We first performed the temperature and magnetic dependent measurements of Bi2Se3 and discovered Shubonikov-de Haas oscillations which verify the quality of single cr...

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Main Author: Xia, Bin
Other Authors: Wang Lan
Format: Theses and Dissertations
Language:English
Published: 2014
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Online Access:https://hdl.handle.net/10356/61654
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-616542023-02-28T23:51:18Z Electric transport studies on topological insulators Xia, Bin Wang Lan School of Physical and Mathematical Sciences DRNTU::Science::Physics::Electricity and magnetism This thesis presents transport experiments performed on topological insulators systems of Bi2Se3, Ca: Bi2Se3 and Bi1.5Sb0.5Te1.8Se1.2. We first performed the temperature and magnetic dependent measurements of Bi2Se3 and discovered Shubonikov-de Haas oscillations which verify the quality of single crystal. Due to the large bulk conduction contributions, we fabricate Bi1.5Sb0.5Te1.8Se1.2 single crystals whose bulk conductions are strongly suppressed. A “Spin-valve” effect has been observed in the CoFe(5nm)/ Bi1.5Sb0.5Te1.8Se1.2 structure and it may be originated from the interactions between ferromagnetic layer and helical surface states of topological insulator. Moreover, we prepared the nanodevice based on Bi1.5Sb0.5Te1.8Se1.2 nanoflake and observed the two channel conduction mode in the samples. Weak-antilocalization effect and ambipolar field effect were also verified and studied in detail based on the nanodevice by the low temperature electrical transport measurements. Interestingly, the superconducting transition was obtained in the pure Bi2Se3 at the temperature below 4K. We propose that the defects formed during the single crystal growth induce such transitions. DOCTOR OF PHILOSOPHY (SPMS) 2014-07-09T02:48:15Z 2014-07-09T02:48:15Z 2014 2014 Thesis Xia, B. (2014). Electric transport studies on topological insulators. Doctoral thesis, Nanyang Technological University, Singapore. https://hdl.handle.net/10356/61654 10.32657/10356/61654 en 168 p. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic DRNTU::Science::Physics::Electricity and magnetism
spellingShingle DRNTU::Science::Physics::Electricity and magnetism
Xia, Bin
Electric transport studies on topological insulators
description This thesis presents transport experiments performed on topological insulators systems of Bi2Se3, Ca: Bi2Se3 and Bi1.5Sb0.5Te1.8Se1.2. We first performed the temperature and magnetic dependent measurements of Bi2Se3 and discovered Shubonikov-de Haas oscillations which verify the quality of single crystal. Due to the large bulk conduction contributions, we fabricate Bi1.5Sb0.5Te1.8Se1.2 single crystals whose bulk conductions are strongly suppressed. A “Spin-valve” effect has been observed in the CoFe(5nm)/ Bi1.5Sb0.5Te1.8Se1.2 structure and it may be originated from the interactions between ferromagnetic layer and helical surface states of topological insulator. Moreover, we prepared the nanodevice based on Bi1.5Sb0.5Te1.8Se1.2 nanoflake and observed the two channel conduction mode in the samples. Weak-antilocalization effect and ambipolar field effect were also verified and studied in detail based on the nanodevice by the low temperature electrical transport measurements. Interestingly, the superconducting transition was obtained in the pure Bi2Se3 at the temperature below 4K. We propose that the defects formed during the single crystal growth induce such transitions.
author2 Wang Lan
author_facet Wang Lan
Xia, Bin
format Theses and Dissertations
author Xia, Bin
author_sort Xia, Bin
title Electric transport studies on topological insulators
title_short Electric transport studies on topological insulators
title_full Electric transport studies on topological insulators
title_fullStr Electric transport studies on topological insulators
title_full_unstemmed Electric transport studies on topological insulators
title_sort electric transport studies on topological insulators
publishDate 2014
url https://hdl.handle.net/10356/61654
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