| Project/Area Number |
21K13865
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 13020:Semiconductors, optical properties of condensed matter and atomic physics-related
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
ZHANG TIANTIAN 東京工業大学, 理学院, 特任助教 (50875101)
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| Project Period (FY) |
2021-04-01 – 2023-03-31
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| Project Status |
Completed (Fiscal Year 2022)
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| Budget Amount *help |
¥3,380,000 (Direct Cost: ¥2,600,000、Indirect Cost: ¥780,000)
Fiscal Year 2022: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2021: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
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| Keywords | Z2 Dirac points / node-line surface states / chiral phonon theory / truly chiral phonons / new surface states / kagome node-line metal / topological band theory / topological materials / Dirac points / chiral phonon / DFT calculation / DFT / chiral phonons / topological material / phononic material |
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| Outline of Research at the Start |
Phonons are also important (quasi)particles in solids, but studies on their topology are not as much as in electrons. They have unique properties which may lead to discoveries of new topological aspects of phonons, such as new quantum degrees of freedoms (e.g., pseudospin), phonon angular momentum, fragile topological phonons.
We will theoretically explore new aspects of topological phonons, including new topological aspects, searching and studying for materials with new topological phonons, collaborations with experimental groups, and extending the results of phonons to other quasiparticles.
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| Outline of Final Research Achievements |
I proposed node-line surface phonon material SnIP, kagome node-line metal Ni3In2S2 (which is also domenstrated by experiments), Z2 Dirac point with multi-helicoid surface states. I built the theory for chiral phonons in non-symmorphic systems and systems with approximate screw symmetry, and demonstrate the truly chiral phonon in HgS together with Raman scattering collaboraters.
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| Academic Significance and Societal Importance of the Research Achievements |
The first proposed node-line surface phonon material SnIP and Z2 Dirac point with multi-helicoid surface states promote the topological band theory. Theories on chiral phonons in non-symmorphic/approximate symmetry systems will triger follow-up studies, and open new avenues in this field.
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