National Institute for Materials Science

Automatic Termination Strategy of Inelastic Neutron-scattering Measurement Using Bayesian Optimization for Bin-width Selection

Currently, an excessive amount of event data is being obtained in four-dimensional inelastic neutron-scattering experiments. A method for automatic bin-width optimization of multidimensional histograms has been developed and recently validated on real inelastic neutron-scattering...

Influences of Nanostructuring and Densification Processes on the Lattice Thermal Conductivity of n -Type Indium Antimonide

Abstract Indium antimonide (InSb), an n-type narrow-band gap semiconductor, has attracted considerable interest in intermediate-temperature thermoelectric (TE) applications due to its excellent electronic transport properties; however, its relatively high lattice thermal conducti...

Anomalous EL–PL Lifetime Inversion in Silicon Quantum-Dot Light-Emitting Diodes

Abstract Diamond-cubic silicon is a promising quantum-dot material for sustainable optoelectronics owing to its abundance, nontoxicity, and size-tunable photoluminescence (PL). However, silicon quantum-dot light-emitting diodes (Si-QLEDs) suffer from severe efficiency roll-off at...

Layer-polarized PN and point junctions in double bilayer graphene

We fabricate twisted double bilayer graphene devices with zero twist angle and a set of local top and bottom gates aligned perpendicularly to each other. A 1D PN junction can be electrostatically defined when the gate voltages applied to the top gates are the same but different o...

Probing spin configurations in exchange-coupled magnetic bilayers with orthogonal anisotropies via anomalous Hall and Nernst effects

When two ferromagnetic thin films with different magnetic easy axes are coupled via the exchange interaction, the magnetization process becomes nontrivial. In this paper, we demonstrate that three-dimensional magnetization information in such a bilayer system can be accessed elec...

Framework nanoarchitectonics of fullerene-derived catalyst

In this review article, we examine the significance of developing catalysts via nanoarchitectonics by focusing on fullerenes as the primary material and frameworks as the nanoscale structural motif. Nanoscale frameworks such as C 60 , MOFs, and 2D carbon networks enable a precise...

Water Activity Governs Ice Nanocrystal Evolution in Rapidly Frozen Sugar Solutions

Abstract Formation and evolution of ice nanocrystals in rapidly frozen sugar solutions were investigated using spin-contrast-variation small-angle neutron scattering (SCV-SANS). As the sugar concentration decreased, the SCV-SANS signal from nanocrystalline ice plates decreased re...

Bandwidth-Limited Critical Currents in Electrically Tunable Moire Bands

Abstract Moiré superlattices host narrow minibands whose bandwidth governs correlated and topological phases. Here, we demonstrate that the bandwidth also sets the critical current for the onset of out-of-equilibrium transport. In bilayer graphene aligned to hexagonal boron nitr...

Octahedral tilt relaxation decoupled from lattice parameters in epitaxial perovskite oxide films

Epitaxial strain in perovskite oxide thin films is conventionally understood through lattice parameter modulation, characterized by the c / a ratio of the pseudocubic cell. However, internal atomic arrangements such as octahedral tilting can relax independently, a phenomenon that...

Unsupervised machine learning for automated crystal orientation mapping on noisy 4D-STEM data

Abstract Four-dimensional scanning transmission electron microscopy (4D-STEM) is a high-throughput measurement used to comprehensively acquire diffraction patterns across a region of interest in a specimen. While the measurement is useful for identifying crystallographic microstr...

Observation of orbital-angular-momentum-driven temperature modulation via the spin Peltier effect

Angular-momentum transport provides a pathway for controlling energy flow in solids beyond conventional charge-based mechanisms. Although spin currents are known to mediate spin-caloritronic phenomena such as the spin Peltier effect (SPE), the role of orbital angular momentum (OA...

Remote Moire Modulation of Decoupled Dirac Subsystems in Twisted Trilayer Graphene

Abstract Moiré superlattices are generally assumed to act only at the interface where lattice mismatch or twist occurs. Here, we study charge transport in large-angle helical twisted trilayer graphene, where interlayer tunneling is strongly reduced. When only the top monolayer g...

A High-Density Supercritical Fluid of H2

Abstract This study aimed to elucidate the structural evolution of supercritical fluid hydrogen (SCF H2) under high pressure. X-ray diffraction was performed on SCF H2 using synchrotron radiation at room temperature. The structure factor S(Q) was observed in a low-Q region at eac...

Hydrogen-bonded supramolecular assembly of didodecylmelamine and thymine at the air/water interface studied by heterodyne-detected vibrational sum frequency generation

Langmuir monolayers of didodecylmelamine (2C12mela) on thymine aqueous solutions were studied by in situ heterodyne-detected vibrational sum frequency generation (HD-VSFG) spectroscopy. The HD-VSFG spectrum of the monolayer on a 10 mM thymine aqueous solution exhibited a positive...

Sliding Disassembly of van der Waals Heterostructures

Abstract Many recent advances in our understanding of two-dimensional electron systems stem from van der Waals (vdW) heterostructures. The assembly process relies on the weak bonding across interfaces between layered vdW compounds, making it possible to construct exceptionally cl...

CO‐Tolerant Ethylene Glycol Oxidation on p–d Hybridized Platinum Ditelluride for Seawater Artificial Leaves

ABSTRACT Seawater‐based artificial leaves are fundamentally constrained by anodic surface poisoning and insufficient photovoltage for bias‐free reaction under complex electrolytes. Here we report a pH‐gradient photoelectrochemical–electrochemical (PEC–EC) system that couples phot...

Orbital-Selective Coexistence of Interlayer Spin-Singlet Formation and SDW Order with Anomalous Spin Reconfiguration in Bilayer Nickelate La 3 Ni 2 O 7 Revealed by 17 O-NMR

The spin structure of the spin density wave (SDW) order in the bilayer nickelate La 3 Ni 2 O 7 has been investigated using site-selective 17 O-NMR measurements on the inner apical O(1), outer apical O(2), and planar O(3,4) sites. Below T SDW (= 150 K), the peak of all planar O(3,...

Coulomb Blockade in Graphene Nano-islands Formed by Direct CVD Growth on Si/SiO 2 Substrate

Graphene nano-islands (GNIs) are promising building blocks for quantum devices owing to their unique potential. However, direct electrical measurements of GNIs have been challenging due to the requirement of metal catalysts in typical synthesis methods. In this study, we demonstr...

Strain Correlated Linearly Polarized Photoluminescence in WSe2/WS2 Moire Superlattices

Abstract Reliable optical control of valley degrees of freedom in moiré excitons requires that the emitted polarization faithfully reflects the underlying valley state. Here, we show that linearly polarized photoluminescence from WSe2/WS2 moiré excitons is largely insensitive t...

Circularly Polarized Electroluminescence and Spin‐Polarized Carrier Transport in Chiral‐Doped Polymer Films

ABSTRACT Circularly polarized electroluminescence (CPEL) based on spin‐dependent light emission is of considerable interest for functional chiral optoelectronics and spin‐photonic applications. Here we report CPEL from devices incorporating achiral poly(9,9‐dioctylfluorene) (PFO)...