The alpha cluster states of 16C are investigated by using the antisymmetrized molecular dynamics. It is shown that two different types of alpha cluster states exist: triangular and linear-chain states. The former has an approximate isosceles triangul
ar configuration of alpha particles surrounded by four valence neutrons occupying sd-shell, while the latter has the linearly aligned alpha particles with two sd-shell neutrons and two pf-shell neutrons. It is found that the structure of the linear-chain state is qualitatively understood in terms of the 3/2 pi- and 1/2 sigma- molecular orbit as predicted by molecular-orbital model, but there exists non-negligible Be+alpha+2n correlation. The band-head energies of the triangular and linear-chain rotational bands are 8.0 and 15.5 MeV, and the latter is close to the He+Be threshold energy. It is also shown that the linear-chain state becomes the yrast sstate at J=10 with excitation energy 27.8 MeV owing to its very large moment-of-inertia comparable with hyperdeformation.
Soft-x-ray photoemission and absorption spectroscopies are employed to investigate the electronic structures of Sr_{1-x}Rh_{2}O_{4}. Similarly to the layered cobaltates such as Na_{1-x}CoO_{2}, a valence-band satellite feature (VBS) occurs at higher
binding energy to the O 2p band. We find that the VBS resonates at the O 1s edge. Additionally, core absorption shows clear x dependence in the O 1s edge rather than in the Rh 3p edge. These results indicate that the holes in the initial state mainly have O 2p character presumably due to d-p rehybridizations affected by Sr^{2+} vacancy potentials. The resultant inhomogenous charge texture may have impact on the TE transport properties at low x.
We have performed ultrahigh-resolution angle-resolved photoemission spectroscopy to directly observe the large superconducting (SC) gap anisotropy (GA) of YNi2B2C. The result shows large SC GA with a smooth variation along an intersection of a Fermi
surface (FS) around the $Gamma$-Z line and nearly isotropic SC gap values for two intersections of FSs around the X-P line but with a point-like non-zero minimum only for one sheet. The point-like SC gap minimum can be connected by the nesting vector reported from band calculations. The results show unexpectedly complicated SC GA of borocarbide superconductors.
We have performed temperature (T) - dependent laser-photoemission spectroscopy of antiferromagnetic (AF) superconductor ErNi2B2C to study the electronic-structure evolution reflecting the interplay between antiferromagnetism and superconductivity. Th
e spectra at the superconducting (SC) phase show a very broad spectral shape. T-dependent SC gap shows a sudden deviation from the BCS prediction just below TN. This observation can be well explained by the theoretical model and thus represents characteristic bulk electronic structure of the AF SC phase for the first time.
Thermoreflectance methods by picosecond pulse heating and by nanosecond pulse heating have been developed under the same geometrical configuration as the laser flash method by the National Metrology Institute of JAPAN, AIST. Using these light pulse h
eating methods, thermal diffusivity of each layer of multilayered thin films and boundary thermal resistance between the layers can be determined from the observed transient temperature curves based on the response function method. The measurement results of various thin films as transparent conductive films used for flat panel displays, hard coating films and multilayered films of the next generation phase-change optical disk will be presented.
