Fluctuation of the orbital/charge degree of freedom and novel physical properties in strongly correlated electron systems

2021 Fiscal Year Final Research Report

• Project/Area Number: 19H01853
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 13030:Magnetism, superconductivity and strongly correlated systems-related
• Research Institution: Waseda University
• Principal Investigator: Katsufuji Takuro 早稲田大学, 理工学術院, 教授 (00272386)
• Co-Investigator(Kenkyū-buntansha): 奥田 哲治 鹿児島大学, 理工学域工学系, 准教授 (20347082) ; 溝川 貴司 早稲田大学, 理工学術院, 教授 (90251397)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 軌道自由度 / 揺らぎ / 核生成-核成長 / 一軸歪 / 光誘起現象

Outline of Final Research Achievements

We have experimentally investigated novel properties of transition metal oxides caused by spatial and temporal fluctuations in the orbital degrees of freedom of d electrons. We found dynamics of phase transitions dominated by a nucleation-growth process in orbital-ordered V oxides. Also, we found that the orbital correlation can be controlled by the strain, which is an external field conjugate to the orbital degrees of freedom, by optical measurements under uniaxial strain. Furthermore, we found a characteristic selection rule in the melting of orbital ordering by the irradiation of a laser pulse.

Free Research Field

数物系科学

Academic Significance and Societal Importance of the Research Achievements

電子間のクーロン相互作用の強い強相関電子系において、電荷、スピン、軌道といった電子の複数の自由度に基づくマルチファンクショナルなデバイスや、巨大な外場応答を用いたデバイスが期待されている。その中で、軌道/電荷自由度の静的な秩序だけでなく、動的・空間的な揺らぎの様子を明らかにすることによって、より進んだ機能を発現することが可能になる。