Experimental study of the new quantum phases and quantum criticalities for hybridized multipole

2018 Fiscal Year Final Research Report

• Project/Area Number: 17H06602
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Single-year Grants
• Research Field: Condensed matter physics II
• Research Institution: The University of Tokyo
• Principal Investigator: Akito Sakai 東京大学, 物性研究所, 助教 (10806087)
• Project Period (FY): 2017-08-25 – 2019-03-31
• Keywords: 多極子 / トポロジー / 異常ネルンスト効果

Outline of Final Research Achievements

This project was performed to search for the new quantum phases and quantum criticalities in strong correlated multipole systems. As a result, we found PrV2Al20 exhibits ferro-octupole order at low temperatures. Moreover, we found Co2MnGa shows the giant anomalous Nernst effect at room temperature due to the Lifshitz type of quantum criticality of the Weyl points. These results are summarized as the articles and presented in domestic and international conferences including several invited talks. Related to this work, I received the young scientist award from physical society of Japan.

Free Research Field

固体物理

Academic Significance and Societal Importance of the Research Achievements

スピンゆらぎによる超伝導や量子臨界現象の理解が進む一方、多極子による量子物性の理解はあまり進んでいない。本研究は混成する多極子による新しい量子状態の発見を示唆するものであり大きな学術的価値がある。
室温での巨大異常ネルンスト効果を発見し、その発現機構を明らかにしたことは今後の熱電変換やスピントロニクスへの応用を期待させる。またワイル点の量子リフシッツ転移が異常ネルンスト効果の対数的増大に寄与しており、学術的にも大変興味深い。