Faculty of International Social Sciences

Takayuki Isono

  (磯野 貴之)

Profile Information

Affiliation
Faculty of Science Department of Physics, Gakushuin University

J-GLOBAL ID
201801019223189599
researchmap Member ID
B000302245

Research Interests

 2

Awards

 1

Papers

 30
  • Takayuki Isono, Yo Machida, Wataru Fujita
    Journal of the Physical Society of Japan, 89(7) 073707-073707, Jul 15, 2020  Peer-reviewed
  • Yo Machida, Nayuta Matsumoto, Takayuki Isono, Kamran Behnia
    Science, 367(6475) 309-312, Jan, 2020  Peer-reviewed
  • Shiori Sugiura, Takayuki Isono, Taichi Terashima, Syuma Yasuzuka, John A. Schlueter, Shinya Uji
    npj Quantum Materials, 4(1), Dec, 2019  Peer-reviewed
    Superconductivity is one of the most intriguing topics in solid state physics. Generally, the superconducting Cooper pairs are broken by the Zeeman effect, which gives the so-called Pauli paramagnetic limit H-Pauli. However, when the superconductivity is in the clean limit and the orbital effect is strongly quenched, the Cooper pairs can survive even above H-Pauli, which is the so-called Fulde and Ferrell, and Larkin and Ovchinnikov (FFLO) phase. Extensive efforts have been devoted to the discovery of the FFLO phase. However, vortex phase transitions have given rise to considerable ambiguity in the interpretation of the experimental data. Here, we report comprehensive magnetocaloric and torque studies of the FFLO phase transition in a highly two-dimensional organic superconductor. We observe the FFLO phase transition clearly distinct from vortex melting transitions. The phase diagram provides crucial information on the stability of the FFLO phase in magnetic fields.
  • Akira Ueda, Kouki Kishimoto, Takayuki Isono, Shota Yamada, Hiromichi Kamo, Kensuke Kobayashi, Reiji Kumai, Youichi Murakami, Jun Gouchi, Yoshiya Uwatoko, Yutaka Nishio, Hatsumi Mori
    RSC Advances, 9 18353-18358, 2019  Peer-reviewed
  • Takayuki Isono, Shiori Sugiura, Taichi Terashima, Kazuya Miyagawa, Kazushi Kanoda, Shinya Uji
    Nature Communications, 9(1), Dec 1, 2018  Peer-reviewed
    A quantum spin liquid (QSL) is an exotic state of matter in condensed-matter systems, where the electron spins are strongly correlated, but conventional magnetic orders are suppressed down to zero temperature because of strong quantum fluctuations. One of the most prominent features of a QSL is the presence of fractionalized spin excitations, called spinons. Despite extensive studies, the nature of the spinons is still highly controversial. Here we report magnetocaloric-effect measurements on an organic spin-1/2 triangular-lattice antiferromagnet, showing that electron spins are decoupled from a lattice in a QSL state. The decoupling phenomena support the gapless nature of spin excitations. We further find that as a magnetic field is applied away from a quantum critical point, the number of spin states that interact with lattice vibrations is strongly reduced, leading to weak spin-lattice coupling. The results are compared with a model of a strongly correlated QSL near a quantum critical point.

Misc.

 8

Teaching Experience

 2

Professional Memberships

 1

Research Projects

 4