Copper oxide nanowires with good crystallinity and high aspect ratio have been attractive for use in high-performance optical and electronic devices. In this work, we fabricated copper oxide nanowires by thermal oxidation method. Copper oxide nanowires were fabricated at various heating times, keeping at a heating temperature of 500℃. When the heating time was over 30 minutes, the average width of the nanowires reached about 100 nm. It was observed that the bottom part of the nanowire was thick compared to the top part. We investigated the detailed structure by using micro-raman spectroscopy and electron backscatter diffraction (EBSD). From the results of raman spectra and EBSD crystal orientation mappings, it was found that Cu₂O/CuO heterostructure is formed at the thick region of the nanowire. Two type of heterostructures were confirmed, namely Cu₂O(110)/CuO(001) and Cu₂O(110)/CuO(110).

Diradical molecules express various functions with potential applications in molecular devices. In such applications, these molecules are often immobilised by surfaces. Diradical character is a feature amount of the diradical state, and it can be defined by first principle molecular orbital calculation. However, it is inpossible to directly estimate the diradical character by DFT/plane-wave calculations, which is the general first-principles calculation method for surface systems – limiting our understanding of the impact of surface effects on diradical. Therefore, it is necessary to establish a estimation scheme of diradical character using the standard outputs of DFT/plane-wave (e.g., electron density). In this study, we introduce a novel method for estimating diradical character based on electron density, and the surface effects are characterised using the developed scheme with results quantified based on density functional theory.

Ionic liquids have high potential as novel lubricants. In this report, lubricating properties and friction interface structure of cyano-based ionic liquids were investigated. Based on the results of friction coefficient and surface analysis, the formation of adsorption layer by electrical interaction with friction surface achieved friction reduction. These results suggest that the friction coefficient can be controlled by applying an electric potential to the friction surface. This report tested this hypothesis. As a result, this verification experiments were successful in changing the friction coefficient.

Under the competition of ferromagnetic interaction and Dzyaloshinskii-Moriya interaction, magnetic vortices in real-space, skyrmions, can be induced on a topological insulator (TI), which reflects the chiral spin structure on the gapped Dirac cone in the momentum space. Here, we observe skyrmions emerge on surfaces of two self-assembled ferromagnetic TI layers, Mn(Bi_1－xSb_x)₂Te₄, separated by a spacer of non-magnetic TI layer, (Bi_1－xSb_x)₂Te₃, through topological Hall effect (THE) by tuning the Fermi level with optimizing the Bi/Sb ratio. By the spacer-thickness-dependence of the magnitude of THE, we find that the moderate coupling of surface states between the top and bottom Mn(Bi_1－xSb_x)₂Te₄ layers is essentially important for inducing and stabilizing skyrmions. Moreover, the highly-ordered Mn atoms in the Mn(Bi_1－xSb_x)₂Te₄ lead to a strong exchange interaction therein, making skyrmions “soft magnetic”. This would open an avenue toward a topologically robust easy-rewritable novel magnetic memory for spintronics.

Electronic devices realize functions such as switches and memories by controlling the movement of electrons. On the other hand, the movement of electrons is known to govern chemical reactions. Therefore, electronic devices are expected to provide the ability to control various chemical reactions. This paper describes a method of controlling chemical reactions by voltages used in the operation of field-effect transistors, a representative electronic device. Unlike conventional electrochemical cells, this methodology can be applied to gas-phase reactions as well as liquid-phase reactions. Sample structures that do not require the application of voltage are also briefly introduced. This paper offers further possibilities for the methodology of electrical control of chemical reactions, which could be widely used by researchers in the fields of chemistry and electronics.

Direct Simulation Monte Carlo (DSMC) methods are widely used to simulate rarefied gas dynamics phenomena. However, it is well known that the performances are remarkably degrade in continuous flow region. This problem inhibits all-Knudsen DSMC simulations. One of reasons is conventional DSMC is spatially first order accuracy. We solved the problem by constructing spatially second-order accuracy DSMC using cell reconstructed interpolation (CRI), and used new limited maximum collision number method (LMCM). As the result, we achieved less computation cost. In this article, the two new methods are presented.

Total reflection neutron induced γ spectroscopy (TN-γ) is a novel promising analytical method suitable for probing chemical composition in the layers and interfaces deeply buried under thick protection materials. The method measures prompt γ-ray spectra from specific elements in the sample, when neutrons impinge at grazing incidence and are reflected at specific surfaces/interfaces. The instrument has been developed at BL10, J-PARC Materials and Life Science Experimental Facility. Unlike ordinary prompt γ-ray Spectroscopy for solid samples, the experiment only uses very limited small size of neutron beam. Therefore, both reducing background significantly and designing optimum geometry for a γ detector are extremely important. The present paper describes the instrumentation and reports the first successful measurements of ¹¹⁵In γ-ray spectra from InP substrate under the neutron total reflection condition.