2017 Fiscal Year Final Research Report
Development of new high-performance thermoelectric conversion materials using dislocations in topological insulators
| Project/Area Number |
16K14371
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| Research Category |
Grant-in-Aid for Challenging Exploratory Research
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| Allocation Type | Multi-year Fund |
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| Research Field |
Physical properties of metals/Metal-base materials
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| Research Institution | The University of Tokyo |
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Principal Investigator |
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| Co-Investigator(Renkei-kenkyūsha) |
Tokumoto Yuki 東京大学, 生産技術研究所, 講師 (20546866)
Kamimura Yasushi 東京大学, 生産技術研究所, 助教 (40291314)
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| Research Collaborator |
Hamasaki Hiromu 東京大学, 大学院工学系研究科, 大学院生
Hattori Yuya 東京大学, 大学院工学系研究科, 大学院生
Kamiyama Ryosuke 東京大学, 大学院工学系研究科, 大学院生
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| Project Period (FY) |
2016-04-01 – 2018-03-31
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| Keywords | トポロジカル絶縁体 / 転位 / 熱電変換材料 / 狭ギャップ半導体 |
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| Outline of Final Research Achievements |
We experimentally investigated the theoretically predicted dislocation conduction in Bi-Sb topological insulator (TI). We grew single crystals of Bi-Sb by unidirectional solidification under a controlled temperature gradient. Then, we plastically deformed the crystals to introduce dislocations. High-density dislocations with the Burgers vector satisfying the conductivity condition were introduced, which were dominantly of the edge type. We performed conductivity measurements for undeformed and deformed samples. The results for the deformed samples in different orientations, parallel and perpendicular to the edge components of dislocations, showed excess conductivity due to dislocation conduction, which can be attributed to the formation of 1D propagating states along dislocations in the 3D TI.
We also fabricated Pb-(Bi,Sb)-Te TI crystals with various Sb molar ratios, and performed a systematic study of their transport properties. We succeeded in improving bulk insulation.
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| Free Research Field |
材料科学
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