New 124-type structure rare-earth compound and investigation into ultrahigh-pressure novel phase of matter

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K13523
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Condensed matter physics II
• Research Institution: The University of Tokyo
• Principal Investigator: KITAGAWA Kentaro 東京大学, 大学院理学系研究科(理学部), 講師 (90567661)
• Co-Investigator(Kenkyū-buntansha): 松林 和幸 電気通信大学, 大学院情報理工学研究科, 准教授 (10451890)
• Research Collaborator: TAKAGI HIDENORI 東京大学, 大学院理学系研究科, 教授 (40187935) ; TAKAYAMA TOMOHIRO Max Planck Institute for Solid State Research, Department of Quantum Materials, Scientist
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 超高圧技術 / 核磁気共鳴 / スピン液体 / 重い電子系 / Ir化合物 / Yb化合物

Outline of Final Research Achievements

We have investigated new structure material, which we discovered previously, and ultrahigh-pressure new phenomena for various materials. We have drawn a pressure-temperature phase diagram for a new material YbCo2Ge4, and found that a quantum critical point is located at as low as 1GPa. Next, we focused on Kitaev quantum spin liquid, which has attracted a lot of attention when we started this program. We discovered the first spin liquid material H3LiIr2O6 as a candidate for such a liquid, where it exhibits paramagnetism down to 50mK and peculiar Dirac-like fermionic dispersions. In a cousin hyperhoneycomb-type beta-Li2IrO6 compound, we reported a competition between the magnetic phase and spin-singlet dimer formation under ultrahigh pressures.

Free Research Field

固体物理学