Spin freezing and unconventional superconductivity

量子物理学・ナノサイエンス第41回特別セミナー

概要

Multiorbital Hubbard systems with Hund coupling exhibit a sharp crossover, as a function of filling or interaction, between a conventional metal state and a non-Fermi liquid metal state with frozen magnetic moments. The fluctuating local moments at the border of this spin-frozen regime induce an instability to a spin-triplet superconducting phase [1]. In multiorbital systems with effectively negative Hund coupling, there is a closely related orbital freezing phenomenon, which is connected to an unconventional type of spin-singlet superconductivity realized in fulleride compounds [2]. In this talk, I will use dynamical mean field simulations to illustrate and discuss these phenomena. By a suitable basis transformation, one can even connect the d-wave superconducting instability in the 2D Hubbard model to a spin-freezing phenomenon [3].

1. [1]S. Hoshino and P. Werner, Phys. Rev. Lett. 115, 247001 (2015)
2. [2]K. Steiner, S. Hoshino, Y. Nomura, and P. Werner, Phys. Rev. B 94, 075107 (2016)
3. [3]P. Werner, S. Hoshino, and H. Shinaoka, Phys. Rev. B 94, 245134 (2016)

• 量子物理学・ナノサイエンス第41回特別セミナー

• ナノサイエンス・量子物理学国際研究センター 主催
• 東京工業大学理学院・物理学系、「ナノサイエンスを拓く量子物理学拠点」共催