Butsuri
Online ISSN : 2423-8872
Print ISSN : 0029-0181
ISSN-L : 0029-0181
Volume 75 , Issue 10
Showing 1-20 articles out of 20 articles from the selected issue
Preface
Contents
Trends
Reviews
Researches
  • Keiichi Edagawa
    Type: Researches
    2020 Volume 75 Issue 10 Pages 619-624
    Published: October 05, 2020
    Released: December 10, 2020
    JOURNAL FREE ACCESS

    Quasicrystals are a form of matter having a peculiar type of order, where the structure cannot be described simply by the repetition of a unit cell like conventional crystals. This fact raises the question of how quasicrystals can grow, i.e., how the atoms can arrange themselves to construct such a peculiar order. In this article, we review this problem and present our recent study of an in-situ observation of the growth process of a quasicrystal by high-temperature high-resolution transmission electron microscopy.

    Download PDF (2965K)
  • Hiroshi Watanabe, Hitoshi Seo, Seiji Yunoki
    Type: Researches
    2020 Volume 75 Issue 10 Pages 625-630
    Published: October 05, 2020
    Released: December 10, 2020
    JOURNAL FREE ACCESS

    In the family of quasi-two-dimensional organic conductors κ-(ET)2 X, superconductivity (SC) is observed next to the so-called dimer-Mott insulator. To clarify the mechanism of SC, we study the extended Hubbard model using the variational Monte Carlo method. We show the ground state phase diagram that includes the antiferromagnetic dimer-Mott insulator, several charge-ordered states, and SC. The symmetry of SC is an extended-s+dx2-y2-wave type and is different from the one discussed in cuprate high-temperature superconductors. We also find significant electron-hole asymmetry and change of the symmetry of SC by carrier doping. Our results suggest the importance of the charge fluctuation and geometrical frustration, and provide new perspective to the mechanism of SC in organic conductors.

    Download PDF (1543K)
  • Yoshihiro Aritomo, Yuya Miyamoto, Katsuhisa Nishio
    Type: Researches
    2020 Volume 75 Issue 10 Pages 631-636
    Published: October 05, 2020
    Released: December 10, 2020
    JOURNAL FREE ACCESS

    Nuclear fission is a unique process characteristics to heavy-mass nuclear systems. About 40 years ago, it was observed in the spontaneous fission of fermium (element 100) that fission-fragment mass distribution dramatically changes from the mass-asymmetric distribution in 257Fm to the sharp mass-symmetric shape in 258Fm. In the present work, we investigated the mechanism of this phenomenon using a dynamical model (Langevin calculation). In such a heavy system, a new fission saddle point leading to the sharp symmetric fission emerges and competes with the traditional saddle point connecting to the asymmetric fission. It was found that the unique vibrational motion, which originates from the non-diagonal elements of transport coefficients in the Langevin equation, has the important role in the selection of two types of fission.

    Download PDF (2912K)
Physics Education
feedback
Top