| Project/Area Number |
16K17753
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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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 | Tokyo University of Science |
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Principal Investigator |
Sugimoto Takanori 東京理科大学, 理学部第一部応用物理学科, 講師 (70735662)
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000)
Fiscal Year 2018: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2017: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2016: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
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| Keywords | 磁化プラトー / スピン液体 / スピン伝導度 / 熱伝導度 / 量子スピン / 磁気励起スペクトラム / 磁気スペクトラム / 磁性 / 理論 |
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| Outline of Final Research Achievements |
We theoretically study on thermal and spin conductivities in quantum magnetic ordered states, in order to realize controlling of these conductivities by applying magnetic field. For this sake, we firstly investigate magnetization curves, quantum phase transitions, and magnetic excitations with finite magnetization in several models by using variational matrix-product state method. In magnetization plateau phases which emerge with spontaneously-broken translational symmetry, we have found new magnetic quasi-particles induced by the spontaneously-broken translational symmetry. These magnetic quasi-particles will give an anomaly in spin and thermal conductivities. In addition, we have developed numerical algorithm to calculate finite-temperature spin dynamical properties by using variational matrix-product state method. By using this method, we will clarify the relationship between the new magnetic quasi-particles and spin and thermal conductivities.
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| Academic Significance and Societal Importance of the Research Achievements |
本課題で対象とした、スピンの量子的秩序に基づいた磁気熱流制御は、次世代のICT技術の中核をなす、スピントロニクスやエネルギー制御素子として大きな役割を果たすと期待される。本研究では、まず並進対称性が自発的に破れた磁化プラトーと呼ばれる量子秩序相において、これまで知られていなかった新たな磁気準粒子が発現することを明らかにした。これは基礎物理学的にも重要な発見である。一方、これまで大きな系での計算が困難とされてきたスピン伝導度や熱伝導度を計算するため、行列積状態変分法を改良し、このベンチマークを行った。これも技術的には重要な成果だと言える。
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