We present a search for neutrinoless double-beta (0νββ) decay of 136 Xe using the full KamLAND-Zen 800 dataset with 745 kg of enriched xenon, corresponding to an exposure of 2.097 ton yr of 136 Xe. This updated search benefits from a more than twofold increase in exposure, recovery of photo-sensor gain, and reduced background from muon-induced spallation of xenon. Combining with the search in the previous KamLAND-Zen phase, we obtain a lower limit for the 0νββ decay half-life of T 0ν 1/2 > 3.8 × 10 26 yr at 90% C.L., a factor of 1.7 improvement over the previous limit. The corresponding upper limits on the effective Majorana neutrino mass are in the range 28-122 meV using phenomenological nuclear matrix element calculations.

The surface electronic structure, postdeposition surface passivation, and Schottky barrier height in contact with Pt of PbTiO3 thin films on (001) SrTiO3 were investigated by x-ray photoemission spectroscopy (XPS). Angle-resolved XPS analysis shows that an ∼10-Å-thick surface layer which consists of lead carbonate and lead oxide exists on high-quality PbTiO3 epitaxial films, although the layer can be removed by postdeposition aqueous HNO3 etching. Electronic states associated with this defective surface layer determine the position of the surface Fermi level relative to the band edges of the PbTiO3 film. In situ XPS measurements were carried out during the Pt deposition on as-grown and HNO3-treated PbTiO3 films. The Pb 4f, Ti 2p, and O 1s peaks were observed to shift to higher binding energies during the in situ Pt deposition, consistent with metallization-induced band bending. Although the initial Fermi energies for both Pt-uncoated as-grown and HNO3-treated PbTiO3 differ by ∼0.3eV, the postmetallization Fermi energy lies at 2.4eV above the valence-band maximum after 2 ML (monolayers) of the Pt deposition for both samples. These results suggest that the Fermi level is pinned by interface defect states because the resulting Pt∕PbTiO3 electron Schottky barrier (∼1eV) is substantially smaller than the value derived from recent electronic structure calculations (1.45eV). Consistent with this observation, angle-resolved XPS results indicate that the (001) surface of both as-deposited and HNO3-treated PbTiO3 films decomposes during the initial stages of the Pt deposition and that metallic Pb diffuses into the Pt layer during the Pt deposition, even at room temperature. The presence of the metallic Pb and the resultant formation of a defective interface layer at the Pt∕PbTiO3 (001) interface apparently produce the observed Fermi energy pinning.

Supramolecular control of the π-stacked configuration of aqueous phthalocyanine (Zn[Pc(SO(3))(4)]) was achieved, allowing organization of a J-type slipped-cofacial dimer with per-O-methylated α-cyclodextrin (TMe-α-CDx) by the aid of host-guest interactions. Pristine Zn[Pc(SO(3))(4)] forms nonfluorescent face-to-face aggregates in water. The π-stacked configuration was controlled in the slipped-cofacial dimer, which was formed as a shallow inclusion complex with TMe-α-CDx, giving remarkably enhanced fluorescence with a very small Stokes shift. Organization of the J-type slipped-cofacial dimer as a 2:2 Zn[Pc(SO(3))(4)]-TMe-α-CDx complex was achieved through π-stacking of the unencapsulated segment of Zn[Pc(SO(3))(4)] shallowly encapsulated by a small TMe-α-CDx cavity.

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We found that a magnetic tunnel junction (MTJ) shows two types of memory operation. One is spin torque switching, and the other is electric stress induced resistive switching (RS), which is observed in various metal oxides. A MTJ in RS operation exhibits a resistance ratio of greater than 100, an endurance of more than 400cycles, and data retention in excess of 89h at 85°C, which is suitable for programable switch elements. The MTJ can operate as a programable switch, as well as a storage element, in a field programable gate array.