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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| Format: | Thesis |
| Language: | English |
| Published: |
2014
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| Online Access: | https://hdl.handle.net/10356/61654 |
| _version_ | 1811692604557885440 |
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| author | Xia, Bin |
| author2 | Wang Lan |
| author_facet | Wang Lan Xia, Bin |
| author_sort | Xia, Bin |
| collection | NTU |
| 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. |
| first_indexed | 2024-10-01T06:38:26Z |
| format | Thesis |
| id | ntu-10356/61654 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T06:38:26Z |
| publishDate | 2014 |
| record_format | dspace |
| spelling | ntu-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 |
| spellingShingle | DRNTU::Science::Physics::Electricity and magnetism Xia, Bin Electric transport studies on topological insulators |
| title | 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_short | Electric transport studies on topological insulators |
| title_sort | electric transport studies on topological insulators |
| topic | DRNTU::Science::Physics::Electricity and magnetism |
| url | https://hdl.handle.net/10356/61654 |
| work_keys_str_mv | AT xiabin electrictransportstudiesontopologicalinsulators |