Unconventional electronic states in Nickel dithiolate componds

2017 Fiscal Year Final Research Report

• Project/Area Number: 26400378
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Condensed matter physics II
• Research Institution: Institute of Physical and Chemical Research
• Principal Investigator: Fujiyama Shigeki 国立研究開発法人理化学研究所, 加藤分子物性研究室, 専任研究員 (00342634)
• Co-Investigator(Kenkyū-buntansha): 草本 哲郎 東京大学, 大学院理学系研究科(理学部), 助教 (90585192)
• Project Period (FY): 2014-04-01 – 2018-03-31
• Keywords: 量子スピン液体 / 有機導体 / 金属錯体

Outline of Final Research Achievements

Quantum spin-liquids (QSL) have attracted considerable attention in condensed matter physics. It was previously found that the ac responses of the dielectric constants of the molecular-based quantum spin liquids, β′-EtMe3Sb[Pd(dmit)2]2 and κ-(BEDT-TTF)2Cu2(CN)3, show similar anomalies. However, the macroscopic dielectric constants cannot be compared with theoretical results, which limits quantitative understanding of the charge dynamics of QSL materials.
We measured the NMR in the cation of β′-EtMe3Sb[Pd(dmit)2]2. The nuclear spin-lattice relaxation rates and nuclear spin-spin relaxation rates have maxima caused by low-energy electronic fluctuations. We assign the temperature dependent correlation times with activation energies of Δ= 200 and = 1200 K to the rotations of methyl and ethyl groups. At the Sb site, we found unknown glassy slowing down of the charge fluctuation with a weakly temperature-dependent correlation time, which remains active down to the lowest temperatures.

Free Research Field

物性物理学