| Project/Area Number |
15K13521
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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 |
Condensed matter physics II
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| Research Institution | Kyoto University |
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Principal Investigator |
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| Co-Investigator(Renkei-kenkyūsha) |
MATSUDA Yuji 京都大学, 理学研究科, 教授 (50199816)
NAKATSUJI Satoru 東京大学, 物性研究所, 教授 (70362431)
YASUI Yukio 明治大学, 理工学部, 準教授 (80345850)
UDAGAWA Masafumi 学習院大学, 理学部, 準教授 (80431790)
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| Research Collaborator |
YAMASHITA Takuya
TERAZAWA Daiki
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| Project Period (FY) |
2015-04-01 – 2017-03-31
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| Project Status |
Completed (Fiscal Year 2016)
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| Budget Amount *help |
¥3,770,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥870,000)
Fiscal Year 2016: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
Fiscal Year 2015: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
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| Keywords | 素励起 / スピン液体 / スピンアイス / 熱伝導 / 幾何学的磁気フラストレーション / 磁気素励起 / フラストレーション / 磁気モノポール |
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| Outline of Final Research Achievements |
Quantum spin liquid is a novel ground state of matter where spins are quantum mechanically fluctuating down to absolute zero temperature. Its nature is manifested itself in exotic properties of elementary excitations, such as spin fractionalization and gauge fluctuations. One of the candidates for quantum spin liquid state is quantum spin ice system, where fluctuations are characterized by the exotic elementary excitations, charged monopoles and photon.
In this project, we have studied spin excitations of the quantum spin ice systems, Yb2Ti2O7 and Pr2Zr2O7, by measuring thermal conductivity. In the former, we found that magnetic monopoles propagate coherently in the crystal lattice due to the influence of quantum fluctuations. In the latter, we have observed anomalous enhancement of thermal conductivity at very low temperature. This may be the first observation of photon, which corresponds to gauge fluctuations in quantum spin liquid.
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