| Project/Area Number |
20244056
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Condensed matter physics II
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
TANAKA Hidekazu Tokyo Institute of Technology, 大学院・理工学研究科, 教授 (80188325)
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| Co-Investigator(Kenkyū-buntansha) |
ONO Toshio 東京工業大学, 大学院・理工学研究科, 助教 (40332639)
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| Co-Investigator(Renkei-kenkyūsha) |
KAKURAI Kazuhisa 日本原子力研究開発機構, 量子ビーム応用研究部門, 副部門長 (00204339)
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| Project Period (FY) |
2008 – 2010
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| Project Status |
Completed (Fiscal Year 2010)
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| Budget Amount *help |
¥26,260,000 (Direct Cost: ¥20,200,000、Indirect Cost: ¥6,060,000)
Fiscal Year 2010: ¥7,540,000 (Direct Cost: ¥5,800,000、Indirect Cost: ¥1,740,000)
Fiscal Year 2009: ¥18,720,000 (Direct Cost: ¥14,400,000、Indirect Cost: ¥4,320,000)
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| Keywords | 磁性 / 量子スピン系 / 強磁場 / ボース凝縮 / 量子相転移 / フラストレーション / 物性実験 / 低温物性 / 強磁場物性 / 高圧物性 |
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| Research Abstract |
From the analysis of the phase transition data obtained from specific heat measurement and the lineshape of the ESR spectrum for Tl_<1-x>K_xCuCl_3, we found that the field-induced quantum phase transition is the Bose glass (BG) to BEC transition of triplons and that the critical behavior for the temperature dependence of the transition field is described by the small-exponent characteristic of the BG-BEC transition. Using high-frequency high field ESR, we investigated elementary excitations of a quantum sine-Gordon (SG) spin system KCuGaF_6. We observed many resonance modes including a soliton resonance and breathers up to the third order, which are main elementary excitations characteristic of the quantum SG model. We found that their resonance conditions are beautifully described by the quantum SG field theory. We developed spin 1/2 kagome antiferromagnets Rb_2Cu_3SnF_<12> and Cs_2Cu_3SnF_<12>. We found that the ground state of Rb_2Cu_3SnF_<12> is a spin singlet with an excitation gap. Using inelastic neutron scattering experiments, we observed that a pinwheel valence-bond-solid state is realized in the ground state.
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