Interplay between Structure and Electronic Properties in Organic Conductors

It is known that the ground states of organic conductors have a diversity reflecting the spatial arrangement of the constituent molecules within the unit cell. A systematic theoretical search for the unifying view behind such possible ground states has been made based on the Hartree-Fock mean field approximation not only to the on-site but also to intersite Coulomb interactions with special emphasis on the families of typical organic conductors (TMTCF)$_2X$ and (ET)$_2X$.Comment: 6 pages, 3 figures, proceedings of LT22 (Helsinki, Finland, August 4-11, 1999

Dirac Electrons in Molecular Solids

Electrons in solids are characterized by the energy bands, which indicate that electrons are considered to be "elementary particles" with specific effective masses and g-factors reflecting features of each solid. There are cases where these particles obey dispersion relationship similar to those of Dirac electrons. Examples include graphite and bismuth both of which are known for many years, together with graphene, a single layer of graphite, recently addressed intensively after its realization. Another recent example is a molecular solid, alpha-ET2I3, which is described by an equation similar to Weyl equation with massless Dirac cones but the coordinate axis is tilted because of the location of cones at off-symmetry points. Orbital susceptibility of such Dirac electrons in graphite and bismuth has been known to have striking features not present in ordinary band electrons but resulting from the inter-band matrix elements of magnetic field. Results of theoretical studies on not only orbital susceptibility but also Hall effect of such Dirac electrons in molecular solids with tilting are introduced in this paper.Comment: 6 pages, 3 figure

Upgrading of shielding for rare decay search in CANDLES

In the CANDLES experiment aiming to search for the very rare neutrino-less double beta decays (0νββ) using 48Ca, we introduced a new shielding system for high energy γ-rays from neutron captures in massive materials near the detector, in addition to the background reduction for 232Th decays in the 0νββ target of CaF2 crystals. The method of background reduction and the performance of newly installed shielding system are described

Newly constructed compact accelerator-based neutron facility at AIST

We have constructed a compact accelerator-based neutron facility at the National Institute of Advanced Industrial Science and Technology (AIST) in Japan aiming at development of structural materials of transportation vehicles for weight reduction. The facility consists of electron linear accelerator, neutron source, and a neutron beamline with a measurement hutch. Currently we are commissioning the accelerator and expecting a first neutron beam in 2019