Online ISSN : 2423-8872
Print ISSN : 0029-0181
ISSN-L : 0029-0181
Volume 71, Issue 8
Displaying 1-24 of 24 articles from this issue
70 Challenges and Mysteries in Physics
  • Tadashi Kawamoto, Takehiko Mori
    Article type: Researches
    2016 Volume 71 Issue 8 Pages 541-546
    Published: August 05, 2016
    Released on J-STAGE: November 16, 2016

    We report structural and electronic properties of molecular layered superconductors including polar molecules in an insulating layer, κH-(DMEDO-TSeF)2[Au(CN)4](THF) and the third polymorph of the organic superconductor (BEDT-TTF)2 Ag(CF3)4(TCE). For the first compound, the angular-dependent magnetoresistance shows incoherent interlayer transport. However, two closed Fermi surfaces are observed in quantum oscillation. This indicates that crystallographically independent layers have different charge densities, i.e. interlayer charge disproportionation, which is due to the electric dipole of THF. For the later compound, the crystal consists of alternating stacks of two types of donor sheets, κ- and α′-types, and the unit cell includes four donor layers. This structure is similar to another high-Tc phase, in which the unit cell contains two donor layers. The superconducting transition temperatures are approximately 11.0 and 9.5 K for the four-layered and two-layered phases, respectively. Superconductivity is attributed to the κ-type conducting layer, because the α′-type layer is in a charge-ordered state. This is in agreement with the de Haas–van Alphen oscillation, which indicates that the κ-layer with an effective half-filled band is the conducting layer. In both superconductors, the superconducting layer is sandwiched by polar insulating layers. This reminds us the Ginzburg superconducting mechanism.

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  • Minori Abe
    Article type: Researches
    2016 Volume 71 Issue 8 Pages 547-551
    Published: August 05, 2016
    Released on J-STAGE: November 16, 2016

    Observation of the electric dipole moment (EDM) of an elementary particle is attractive as a probe of CP violation, a necessary condition to explain matter-antimatter asymmetry in universe. In particular, the precision of electron EDM (eEDM) measurements in molecules has been drastically improved nowadays. For the eEDM detection, collaborations of particle physic, atomic molecular optics (AMO), and relativistic quantum chemistry is necessary. This article reviews the basic background of EDM in particle physics, experimental strategy, and relativistic theoretical chemistry to calculate effective electric field (Eeff), a requisite to extract the value of eEDM from an experimental observable. We recently developed a program to calculate Eeff accurately and in this article, we discuss our calculated values of Eeff in YbF and HgX (X: halogen) molecules. HgX are found to be promising candidates of new eEDM experiment because of its large Eeff .

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