Publications by authors named "Iwasawa H"

Electronic inhomogeneity arises ubiquitously as a consequence of adjacent and/or competing multiple phases or orders in strongly correlated electron systems. Gap inhomogeneity in high- cuprate superconductors has been widely observed using scanning tunneling microscopy/spectroscopy. However, it has yet to be evaluated by angle-resolved photoemission spectroscopy (ARPES) due to the difficulty in achieving both high energy and spatial resolutions.

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Article Synopsis
  • * The researchers explore enhancing efficiency by using measurement informatics, specifically Gaussian process regression (GPR) to optimize the collection of spin polarization data.
  • * Their findings indicate that the GPR score can effectively be used as a stopping criterion, allowing for significant time savings of 5-10 times compared to traditional methods in conducting spin-resolved ARPES experiments.
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Article Synopsis
  • Developed a cutting-edge laser-based spectroscopy apparatus (µ-SARPES) for detailed electronic analysis with micrometer resolution.
  • Combines advanced components like a high-resolution spectrometer, focused 6 eV laser, precise sample control, and a spin detector to achieve impressive energy resolution.
  • Demonstrated the system's capabilities through experiments on topological insulators and patterned gold on silicon substrates, revealing intricate electronic structures and spin polarization.
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The role of spin-orbit interaction has been recently reconsidered in high-[Formula: see text] cuprates, stimulated by the recent experimental observations of spin-polarized electronic states. However, due to the complexity of the spin texture reported, the origin of the spin polarization in high-[Formula: see text] cuprates remains unclear. Here, we present the spin- and angle-resolved photoemission spectroscopy (ARPES) data on the facing momentum points that are symmetric with respect to the [Formula: see text] point, to ensure the intrinsic spin nature related to the initial state.

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Although aqueous ammonia is an inexpensive and readily available safe source of ammonia, there have been no successful studies on direct catalytic dehydrative amidations of carboxylic acids with aqueous ammonia. In this study, we report a catalytic methodology for the synthesis of primary amides through diboronic acid anhydride (DBAA)-catalyzed dehydrative condensation of carboxylic acids with aqueous ammonia as the amine substrate.

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An amendment to this paper has been published and can be accessed via a link at the top of the paper.

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Topological semimetals materialize a new state of quantum matter where massless fermions protected by a specific crystal symmetry host exotic quantum phenomena. Distinct from well-known Dirac and Weyl fermions, structurally chiral topological semimetals are predicted to host new types of massless fermions characterized by a large topological charge, whereas such exotic fermions are yet to be experimentally established. Here, by using angle-resolved photoemission spectroscopy, we experimentally demonstrate that a transition-metal silicide CoSi hosts two types of chiral topological fermions, a spin-1 chiral fermion and a double Weyl fermion, in the center and corner of the bulk Brillouin zone, respectively.

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The major breakthroughs in understanding of topological materials over the past decade were all triggered by the discovery of the Z-type topological insulator-a type of material that is insulating in its interior but allows electron flow on its surface. In three dimensions, a topological insulator is classified as either 'strong' or 'weak', and experimental confirmations of the strong topological insulator rapidly followed theoretical predictions. By contrast, the weak topological insulator (WTI) has so far eluded experimental verification, because the topological surface states emerge only on particular side surfaces, which are typically undetectable in real three-dimensional crystals.

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The perceived duration of a visual event is highly related to stimulus attributes. It is well known that a moving stimulus appears to last longer than a static one does. Previous studies have demonstrated that the time dilation in a moving stimulus can be influenced by perceived motion, rather than by mere physical motion, and that a faster motion appears to last longer than a slower one does.

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Angle-resolved photoemission spectroscopy (ARPES) is a powerful experimental technique in materials science, as it can directly probe electronic states inside solids in energy (E) and momentum (k) space. As an advanced technique, spatially-resolved ARPES using a well-focused light source (high-resolution ARPES microscopy) has recently attracted growing interests because of its capability to obtain local electronic information at micro- or nano-metric length scales. However, there exist several technical challenges to guarantee high precision in determining translational and rotational positions in reasonable measurement time.

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In this study, we investigated the correlations between biochemical and hematological test results obtained using microliter-scale fingertip blood samples collected with a newly developed blood collection device and those obtained using conventional venous blood. Eighty volunteer subjects were enrolled in this study. Blood samples were drawn from the fingertip of the ring finger by a single puncture, and 60-µL samples were promptly and accurately aspirated into a blood collection chip.

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Electronic structures of ferromagnetic heavy fermion Yb compounds of YbPdSi, YbPdGe, and YbPtGe are studied by photoelectron spectroscopy around the Yb 4d-4f resonance, resonant x-ray emission spectroscopy at the Yb L absorption edge, and density functional theory combined with dynamical mean field theory calculations. These compounds all have a temperature-independent intermediate Yb valence with large [Formula: see text] and small [Formula: see text] components. The magnitude of the Yb valence is evaluated to be YbPtGe [Formula: see text] YbPdGe [Formula: see text] YbPdSi, suggesting that YbPtGe is the closest to the quantum critical point among the three Yb compounds.

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We have developed a laser-based scanning angle-resolved photoemission spectroscopy system (µ-ARPES) equipped with a high precision 6-axis control system, realizing not only high-resolution photoemission spectroscopy in energy and momentum, but also spatial resolution of a µm scale. This enables our µ-ARPES system to probe fine details of intrinsic electronic states near the Fermi level such as the superconducting gaps and lifetime broadening.

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A rotatable high-resolution angle-resolved photoemission spectroscopy (ARPES) system has been developed to utilize tunable linear-polarization geometries on the linear undulator beamline (BL-1) at Hiroshima Synchrotron Radiation Center. By rotating the whole ARPES measurement system, the photoelectron detection plane can be continuously changed from parallel to normal against the electric field vector of linearly polarized undulator radiation. This polarization tunability enables us to identify the symmetry of the initial electronic states with respect to the mirror planes, and to selectively observe the electronic states based on the dipole selection rule in the photoemission process.

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We have investigated the influence of metal adsorbates (sodium and cobalt) on the occupied and unoccupied electronic structure of MoS(0 0 0 1) and WSe(0 0 0 1), through a combination of both photoemission and inverse photoemission. The electronic structure is rigidly shifted in both the WSe and MoS systems, with either Na or Co adsorption, generally as predicted by accompanying density functional theory based calculations. Na adsorption is found to behave as an electron donor (n-type) in MoS, while Co adsorption acts as an electron acceptor (p-type) in WSe.

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Accelerated fracture healing in patients with spinal cord injuries (SCI) is often encountered in clinical practice. However, there is no distinct evidence in the accelerated fracture healing, and the mechanisms of accelerated fracture healing in SCI are poorly understood. We aimed to determine whether SCI accelerated fracture healing in morphology and strength, to characterize the healing process with SCI, and to clarify the factors responsible for accelerated fracture healing.

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We present angle-resolved photoemission spectroscopy measurements of the quasi-one-dimensional superconductor K_{2}Cr_{3}As_{3}. We find that the Fermi surface contains two Fermi surface sheets, with linearly dispersing bands not displaying any significant band renormalizations. The one-dimensional band dispersions display a suppression of spectral intensity approaching the Fermi level according to a linear power law, over an energy range of ∼200  meV.

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In this study, we investigated the correlations of values of biochemical and hematological tests obtained using microliter-scale fingertip blood samples collected with a newly developed blood collection device with those using conventional venous blood. Eighty volunteer subjects were enrolled in the study. Blood sam- ples were drawn from the fingertip of the ring finger by a single puncture and 60 μL of each sample was promptly and accurately aspirated into a blood collection chip.

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Objective: Moderate mechanical stress generated by normal joint loading and movement is essential for the maintenance of healthy articular cartilage. However, the effects of reduced loading caused by the absence of weight bearing or joint motion on articular cartilage and subchondral bone is still poorly understood. We aimed to characterize morphological and metabolic responses of articular cartilage and subchondral bone to decreased mechanical stress in vivo.

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Background: Contractures are a prevalent and potentially severe complication in patients with neurologic disorders. Although heat, cold, and stretching are commonly used for treatment of contractures and/or spasticity (the cause of many contractures), the sequential effects of these modalities remain unclear.

Questions/purposes: Using an established rat model with spinal cord injury with knee flexion contracture, we sought to determine what combination of heat or cold before stretching is the most effective for treatment of contractures derived from spastic paralyses and investigated which treatment leads to the best (1) improvement in the loss of ROM; (2) restoration of deterioration in the muscular and articular factors responsible for contractures; and (3) amelioration of histopathologic features such as muscular fibrosis in biceps femoris and shortening of the joint capsule.

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The orbital symmetry of the band structure of 2H-WSe2(0 0 0 1) has been investigated by means of angle-resolved photoelectron spectroscopy (ARPES) and density functional theory (DFT). The WSe2(0 0 0 1) experimental band structure is found, by ARPES, to be significantly different for states of even and odd reflection parities along both the [Formula: see text]-[Formula: see text] and [Formula: see text]-[Formula: see text] lines, in good agreement with results obtained from DFT. The light polarization dependence of the photoemission intensities from the top of the valence band for bulk WSe2(0 0 0 1) is explained by the dominance of W 5[Formula: see text] states around the [Formula: see text]-point and W 5d xy states around the [Formula: see text]-point, thus dominated, respectively, by states of even and odd symmetry, with respect to the [Formula: see text]-[Formula: see text] line.

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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 (PtSe2), a new member of the layered TMDs family, by a single step of direct selenization of a Pt(111) substrate. A combination of atomic-resolution experimental characterizations and first-principle theoretic calculations reveals the atomic structure of the monolayer PtSe2/Pt(111).

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Background/aims: Combining peritoneal dialysis (PD) and hemodialysis (HD) has been common treatment option in Japan.

Methods: In this retrospective, multicenter, observational study, the clinical characteristics and outcomes of 104 patients (57 ± 11 years, males 72%) who had switched from PD alone to combined therapy with PD and HD were studied. Clinical parameters were measured at baseline and after 3 months of combined therapy.

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Background: Dietary protein intake (PI) induces glomerular hyperfiltration and reduced dietary PI can be effective in preserving kidney function. However, there is limited information regarding the relationship between dietary PI and glomerular histological changes in chronic kidney disease. We investigated the relationship between changes in dietary PI and both the changes in creatinine clearance and glomerular histomorphometry in adult patients with IgA nephropathy (IgAN).

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We find a wave vector dependence of the band symmetries for MoS(2)(0 0 0 1) in angle-resolved photoemission. The band structures are found to be significantly different for states of even and odd reflection parities, despite the absence of true mirror plane symmetry away from Γ, the Brillouin zone center, along the line to the K point, at the Brillouin zone edge. Our measurements agree with density functional theory (DFT) calculations for each band symmetry, with the notable exception of the Mo 4d(x(2)-y(2)) contributions to the valence band structure of MoS(2)(0 0 0 1).

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