Kenya Shimada

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The Belle detector was designed and constructed to carry out quantitative studies of rare B-meson decay modes with very small branching fractions using an asymmetric e þ e À collider operating at the U(4S) resonance, the KEK-B-factory. Such studies require data samples containing B10 7 B-meson decays. The Belle detector is configured around a 1:5 T(More)
The three-dimensional topological semimetals represent a new quantum state of matter. Distinct from the surface state in the topological insulators that exhibits linear dispersion in two-dimensional momentum plane, the three-dimensional semimetals host bulk band dispersions linearly along all directions. In addition to the gapless points in the bulk, the(More)
The electronic transport properties of conventional three-dimensional metals are successfully described by Fermi-liquid theory. But when the dimensionality of such a system is reduced to one, the Fermi-liquid state becomes unstable to Coulomb interactions, and the conduction electrons should instead behave according to Tomonaga-Luttinger-liquid (TLL)(More)
The unconventional superconductivity in the newly discovered iron-based superconductors is intimately related to its multiband/multiorbital nature. Here we report the comprehensive orbital characters of the low-energy three-dimensional electronic structure in BaFe 1.85 Co 0.15 As 2 by studying the polarization and photon-energy dependence of angle-resolved(More)
We performed angle-resolved photoemission (ARPES) experiments with circularly polarized light and first-principles density functional calculation with spin-orbit coupling to study surface states of a topological insulator Bi2Se3. We observed circular dichroism (CD) as large as 30% in the ARPES data with upper and lower Dirac cones showing opposite signs in(More)
Single-layer transition-metal dichalcogenides (TMDs) receive significant attention due to their intriguing physical properties for both fundamental research and potential applications in electronics, optoelectronics, spintronics, catalysis, and so on. Here, we demonstrate the epitaxial growth of high-quality single-crystal, monolayer platinum diselenide(More)
Unconventional Cooper pairing originating from spin or orbital fluctuations has been proposed for iron-based superconductors. Such pairing may be enhanced by quasi-nesting of two-dimensional electron and hole-like Fermi surfaces (FS), which is considered an important ingredient for superconductivity at high critical temperatures (high-Tc). However, the(More)
We have studied a possibility to read small pits in electron beam (EB) resist layer using a near-field optical probe for ultrahigh density optical storage. For the reading, we used small near-field optical probe in prototype atomic force cantilevered SNOM, which has an ability to obtain both atomic force microscope (AFM) and scanning near-field microscope(More)
We report the experimental identification of a symmetry-protected surface state on Mo(1 1 2). The utilization of photon-energy- and polarization-dependent angle-resolved photoemission spectroscopy clearly demonstrates that this true surface state preserves its two-dimensional character despite the fact that it resides within the projection of the bulk bands(More)