systemaic study of the novel electronic phases in two-bands one-dimensional electronic system

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K03720
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 13030:Magnetism, superconductivity and strongly correlated systems-related
• Research Institution: Fukushima Medical University
• Principal Investigator: Hiraki Ko-ichi 福島県立医科大学, 総合科学教育研究センター, 教授 (00306523)
• Co-Investigator(Kenkyū-buntansha): 松浦 弘泰 東京大学, 大学院理学系研究科(理学部), 助教 (40596607) ; 石井 康之 芝浦工業大学, 工学部, 教授 (90391854)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 一次元伝導体 / NMR / nodalline半金属 / 磁場誘起電荷密度波

Outline of Final Research Achievements

we have conducted both experimental and theoretical studies to clarify the origin of anomalous electronic properties of two-bands one-dimensional system, HMTSF-TCNQ. The contributions of the donor- and the acceptor-chains were decomposed by site selective NMR measurements. We also observed T-cubic temperature dependence of NMR relaxation rate, 1/T1, which supports the band structure obtained by the first principle and tight^binding calculations.
It has been clarifed that the present system is understood as a nodalline semimetal. We also performed NMR measurements under pressure to observe unconventional ``density wave" phase under strong magnetis field and high pressure.The small reduction of the density of state was observed under pressure.

Free Research Field

物性物理学

Academic Significance and Societal Importance of the Research Achievements

本研究は二つの一次元伝導バンドを持つ伝導体HMTSF-TCNQが示す特異な状態の解明をした研究である。1970年台には報告があった異常反磁性は本研究のNMR、磁化率測定、および理論計算によりその起源が明らかにされた。比較的単純なバンド構造と期待されている一次元電子系の電子状態に新たな可能性を見出したという点で意義深い。
一方、圧力下でその存在が議論されている「磁場誘起電荷密度波」についてはさらなる研究が必要である。