Development of pressure induced single-component superconducors and Dirac materials

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K05850
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Functional solid state chemistry
• Research Institution: Institute of Physical and Chemical Research
• Principal Investigator: Cui Hengbo 国立研究開発法人理化学研究所, 開拓研究本部, 研究員 (10425415)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 単一成分分子性伝導体 / ジチオレン金属錯体 / 超伝導体 / ディラック電子系 / 高圧物性 / 高圧結晶構造

Outline of Final Research Achievements

(1),For development of single-component molecular superconductors, [M (hfdt) 2] (M = Au, Pd, Pt) with a dimer structure and two polymorphs of [Pt (hfdt) 2] crystals were synthesized. The electrical resistance under pressure was measured up to 20GPa.82),The high pressure single crystal structure of [Pd (dddt) 2], which is a Dirac electron system under pressure, and the isostructural [Ni (dddt) 2] were measured. The origin of Dirac cone formation mechanisum and the the effect of central metal substitution on high pressure properties were investigated. (3),The high-pressure single crystal synchrotron X-ray diffraction was performed up to 11 GPa. two steps crystal structure transitions were found around 3 GPa and 11 GPa, respectively. Inside dimer, Ni-Se bond at ambient pressure was disappeared and new Ni-Ni bond were formed at 3.1 GPa, and two new Se-Se bonds were formed between two Ni(ddds)2 molecule at 11GPa.

Free Research Field

物理化学

Academic Significance and Societal Importance of the Research Achievements

単一成分分子性伝導体は、今まで研究されている二種類以上の組成からなる分子性伝導体と異なり、結晶中に一種類の分子しか存在しないため、理論的計算や物性の解明が比較的に容易である。特に、単一成分分子性超伝導体とディラック電子系物質は、エネルギー節約材料として期待されことから、材料開発研究において非常に重要な位置を占めている。本研究で得られた結果は、将来の新規単一成分分子性機能材料開発と物性機構解明において新たな方向性と知見が得られた。