Study on charge anomaly in Organic conductor using nuclear quadrupole resonance

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K14401
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 13030:Magnetism, superconductivity and strongly correlated systems-related
• Research Institution: Saitama University
• Principal Investigator: KOBAYASHI Takuya 埼玉大学, 研究機構, 助教 (50827186)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 有機伝導体 / 核四重極共鳴 / 電荷秩序 / 強相関電子系 / 反強磁性 / 超伝導 / 核磁気共鳴

Outline of Final Research Achievements

Organic conductors exhibit a variety of physical properties due to their low dimensionality and electronic correlations, where charge and spin properties are entangled. Nuclear magnetic resonance (NMR) techniques using carbon and hydrogen nuclei with nuclear spins I=1/2 have been used to study the physical properties of organic conductors, but in this case, the nuclear spins interact only with a magnetic field. In this study, I focused on the nuclei with I>1/2, which interact with an electric field gradient in addition to the magnetic field, and pioneered the nuclear quadrupole resonance method in organic conductors. As the results, I have verified the charge ordering pattern in the conducting layers, observed anomalous charge fluctuations, and evaluated the magnitude of the interaction between the conducting layers by using the nuclear spins located in the insulating layers, the information of which cannot be obtained by conventional NMR measurements in organic conductors.

Free Research Field

物性物理

Academic Significance and Societal Importance of the Research Achievements

有機導体は、現代の科学技術で応用されているような金属や半導体とは異なるメカニズムで金属―絶縁体転移を示したり、超伝導や量子スピン液体など今後さらなる応用が期待される量子物性を示すことから物性物理分野において注目されている。本研究は、有機導体の示す物性のメカニズムを解明するとともに、これまでの有機導体の研究では用いられなかった核四重極共鳴という手法を開拓するものである。この手法により、これまで実験的に明らかにされてこなかった有機導体の電子物性のメカニズムや、本研究を通して見つけた新規物性を解明することができた。