A5069760239- Physics of Superconductivity and Magnetism
- Advanced Condensed Matter Physics
- Magnetic and transport properties of perovskites and related materials
- Iron-based superconductors research
- Magnetic properties of thin films
- Boron and Carbon Nanomaterials Research
- Rare-earth and actinide compounds
- Graphene research and applications
- Topological Materials and Phenomena
- Quantum and electron transport phenomena
- X-ray Spectroscopy and Fluorescence Analysis
- Advanced X-ray Imaging Techniques
- MXene and MAX Phase Materials
- Magnetic Properties and Applications
- 2D Materials and Applications
- Diamond and Carbon-based Materials Research
- Electronic and Structural Properties of Oxides
- Superconductivity in MgB2 and Alloys
- Chalcogenide Semiconductor Thin Films
- Magneto-Optical Properties and Applications
- Inorganic Chemistry and Materials
- Corporate Taxation and Avoidance
- Crystallography and Radiation Phenomena
- Ion-surface interactions and analysis
- Intellectual Capital and Performance Analysis
The University of Tokyo
2016-2025
University of Zurich
2018-2025
Institute for Solid State Physics and Optics
2021-2025
NTT Basic Research Laboratories
2015
We present a soft x-ray angle-resolved photoemission spectroscopy study of overdoped high-temperature superconductors. In-plane and out-of-plane components the Fermi surface are mapped by varying angle incident photon energy. No ${k}_{z}$ dispersion is observed along nodal direction, whereas significant antinodal identified for La-based cuprates. Based on tight-binding parametrization, we discuss implications density states near van Hove singularity. Our results suggest that large electronic...
In the hole-doped cuprates, a small amount of carriers suppresses antiferromagnetism and induces superconductivity. electron-doped on other hand, superconductivity appears only in narrow range high electron concentration ($\sim$ doped Ce content) after reduction annealing, strong antiferromagnetic (AFM) correlation persists superconducting phase. Recently, Pr$_{1.3-x}$La$_{0.7}$Ce$_{x}$CuO$_{4}$ (PLCCO) bulk single crystals annealed by "protect annealing" method showed $T_c$ $\sim$ 27 K for...
Abstract The transition temperature T c of unconventional superconductivity is often tunable. For a monolayer FeSe, for example, the sweet spot uniquely bound to titanium-oxide substrates. By contrast La 2−x Sr x CuO 4 thin films, such substrates are sub-optimal and highest instead obtained using LaSrAlO . An outstanding challenge thus understand optimal conditions in films: which microscopic parameters drive change how can we tune them? Here demonstrate, by combination x-ray absorption...
Abstract The minimal ingredients to explain the essential physics of layered copper-oxide (cuprates) materials remains heavily debated. Effective low-energy single-band models copper–oxygen orbitals are widely used because there exists no strong experimental evidence supporting multi-band structures. Here, we report angle-resolved photoelectron spectroscopy experiments on La-based cuprates that provide direct observation a two-band structure. This electronic structure, qualitatively...
The utilization of orbital transport provides a versatile and efficient spin manipulation mechanism. As interest in orbital-mediated grows, we face new issue to identify the underlying physics that determines efficiency torque (OT). In this study, systematically investigate variation OT governed by Rashba-Edelstein effect at Cu/oxide interface, as change oxide material. We find varies factor $\ensuremath{\sim}2$, depending on oxide. Our results suggest active electronic interatomic...
We present an enhanced method for synthesizing sheets of borophane. Despite the challenges associated with low efficiency, we discovered that incorporating hydrochloric acid into ion-exchange reaction significantly improved production yield from 20% to over 50%. After a thorough examination reaction, gained insight underlying mechanisms and found use provides two key benefits: accelerated borophene isolation high-purity products. This has potential pave way novel topological 2D materials...
An unexplored material of copper boride has been realized recently in two-dimensional form at a (111) surface the
The strongly correlated insulator Ca$_{2}$RuO$_4$ is considered as a paradigmatic realization of both spin-orbital physics and band-Mott insulating phase, characterized by orbitally selective coexistence band Mott gap. We present high-resolution oxygen $K$-edge resonant inelastic X-ray scattering study the antiferromagnetic state Ca$_{2}$RuO$_4$. A set low-energy ($\sim$80 400 meV) high-energy ($\sim$1.3 2.2 eV) excitations are reported that show strong incident light polarization...
Static stripe order is detrimental to superconductivity. Yet, it has been proposed that transverse fluctuations may enhance the inter-stripe Josephson coupling and thus promote Direct experimental studies of dynamics, however, remain difficult. From a strong-coupling perspective, are realized in form dynamic "kinks"-sideways shifting sections. Here, we show how modest uniaxial pressure tuning reorganizes directional kink alignment. Our starting point La1.88Sr0.12CuO4 where ordering results...
Abstract In high-temperature cuprate superconductors, stripe order refers broadly to a coupled spin and charge modulation with commensuration of eight four lattice units, respectively. How this evolves across optimal doping remains controversial question. Here we present systematic resonant inelastic x-ray scattering study weak correlations in La 2− x Sr CuO 4 1.8− Eu 0.2 . Ultra high energy resolution experiments demonstrate the importance separation elastic processes. Long-range...
Abstract Van Hove singularities (VHss) in the vicinity of Fermi energy often play a dramatic role physics strongly correlated electron materials. The divergence density states generated by VHss can trigger emergence phases such as superconductivity, ferromagnetism, metamagnetism, and wave orders. A detailed understanding electronic structure these is therefore essential for an accurate description instabilities. Here, we study low-energy trilayer strontium ruthenate Sr 4 Ru 3 O 10 ,...
Abstract Quantum fluctuations in low-dimensional systems and near quantum phase transitions have significant influences on material properties. Yet, it is difficult to experimentally gauge the strength importance of fluctuations. Here we provide a resonant inelastic x-ray scattering study magnon excitations Mott insulating cuprates. From thin film SrCuO 2 , single- bi-magnon dispersions are derived. Using an effective Heisenberg Hamiltonian generated from Hubbard model, show that...
Structural phase separation in AxFe2−ySe2 system has been studied by different experimental techniques, however, it should be important to know how the electronic uniformity is influenced, on which length scale phases coexist and what their spatial distribution. Here, we have used novel scanning photoelectron microscopy (SPEM) study KxFe2−ySe2, providing a direct measurement of topological distribution phases. The SPEM results reveal peculiar interconnected conducting filamentary that...
We use resonant inelastic x-ray scattering to investigate charge-stripe correlations in La$_{1.675}$Eu$_{0.2}$Sr$_{0.125}$CuO$_4$. By differentiating elastic from scattering, it is demonstrated that precede both the structural low-temperature tetragonal phase and transport-defined pseudogap onset. The peak amplitude charge stripes decays approximately as $T^{-2}$ towards our detection limit. in-plane integrated intensity, however, remains roughly temperature independent. Therefore, although...
Electron-phonon and electron-electron interactions are found to cooperatively drive the long-range charge order in cuprates.
We systematically investigated electronic evolutions of nonsymmorphic borophene with chemical environments that were realized by the ion exchange method. Electronic structures can be characterized topological Z2 invariant. Spectroscopic experiments and DFT calculations unveiled a sheet hydrogenated (borophane) is Dirac nodal loop semimetal (Z2=−1), while layered crystal YCrB4 an insulator (Z2=1). The results demonstrate transition replacement counter atoms on layer.
The structure and chemical state of a boron chain, isoelectronic to polycumulene, were obtained with combination positron diffraction, photoelectron spectroscopy, first-principles calculations. In the present work, an array chains was found in copper boride layer on metal crystal substrate. band this material determined be electronically doped hybridized by neighboring atoms. These atom exhibit unique electrophilic character that is specific element. properties substrate effect are...
Sulfur vacancy on an MoS2 basal plane plays a crucial role in device performance and catalytic activity; thus, understanding of the electronic states sulfur vacancies is still important issue. We investigate by ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) density functional theory calculations while heating system hydrogen. The AP-XPS results show decrease intensity ratio S 2p to Mo 3d, indicating that are formed. Furthermore, low-energy components observed 3d spectra. To...
The structure of an Al(111)3×3-Si surface was examined by combining data from positron diffraction and core-level photoemission spectroscopy. Analysis the rocking curves indicated that overlayer had a flat honeycomb lattice structure. Simulations Si spectra calculated via first principles one atoms in unit cell replaced Al atom. superstructure thus two-dimensional layer Al-embedded silicene on Al(111). locked icon Physics Subject Headings (PhySH)Electronic structureSurface & interfacial...
Mixing solutions and evaluating their concentrations are common often critical tasks in laboratory experiments. Traditionally, these have been conducted though manual optimization by sampling across all conditions. Here, we present an alternative approach adopting a robotic system integrated with Bayesian whereby solvents automatically autonomously mixed to the desired concentration. The solution control has robot-controlled pipette optical transmission setup that makes both liquid...
The discovery of fullerene following the synthesis graphene marked a paradigm shift in chemistry. Here, we report biycycloborane, arising from borophane (hydrogen boride). Uniquely, this method involves decomposition mechanism rather than traditional atom-by-atom assembly, marking an unique approach to constructing complex borane structures. mass spectrometry unveiled that stable molecule has 178 atomic unit with stoichiometry B14H26. Optical spectra and simulations further evidenced its...
The anomalous Hall {\color{black} e}ffect (AHE) has emerged as a key indicator of time-reversal symmetry breaking (TRSB) and topological features in electronic band structures. Absent magnetic field, the AHE requires spontaneous TRSB but proven hard to probe due averaging over domains. component effect is thus frequently derived from extrapolating field dependence response. We show that discerning whether an intrinsic property free system becomes intricate presence strong fluctuations....